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Online Dental Magazine

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Welcome To Guident

Welcome To Guident

Welcome to Guident our online dental magazine. Guident is a globally well-known online international dental journal/publication that is circulated in India as well as globally. The journal is designed to help dentists to build long-term dentistry career success by providing them knowledge to optimize their practice performance during changing times. The field of dentistry has gone through a phase of transformation from in the last century with many new advances and technologies coming up. The complete dental profession is on the verge of many new innovations. To keep all the people associated with this profession we provide our dental magazine ‘Guident’. Our magazine upgrades the knowledge of professionals with information about the latest achievements and advances in the field. Our journal is an online international dental journal which is internationally indexed. The Journal is globally acclaimed in terms of dentistry Knowledge and information; it has been reviewed by many professional dentists of all over the world. Despite the advances in healthcare segments, the Indian population continues to be affected by numerous oral diseases. These dental problems have encouraged people to search and opt for professional dental healthcare services including Endodontic, Prosthodontics, Orthodontic, Periodontics, Implantology, Pedodontics, and Cosmetic dental services etc. Young professionals and experienced dentists skilled in these and many more advanced dentistry services need to constantly keep themselves updated in order to deliver the best treatment to the seekers of such facilities. GUIDENT Indexed by globally known hosts like ProQuest, EBSCO Host and Ulrichsweb Global Series Directory, the journal has been reviewed by numerous professional dentists practicing across the world. This rich storehouse of dental data is easy to access and can be referred to any minute, even when you are mobile. Serving as your ready reckoner, Guident aims to bring the global dental information at your fingertip to add an ultra-modern touch to your dental practice so that you can help your patients smile forever.

Oral Pathology

Authors: Dr. N.N. Singh, (Professor and Head),Dr. (Mrs) V.R.Brave (Professor), Dr. G. Sreedhar (Associate Professor),

Introduction :
Dental and medical treatment for loss of tissue or end stage organ failure is required by all1. The field of tissue engineering has developed over the past decade to recreate functional, healthy tissues and organs in order to replace diseased, dying or dead tissues1 .The amalgamation of bioengineering & dentistry has resulted in explosion of knowledge that has enhanced our understanding and started a new era of dentistry, enabling us to restore the lost tissue function.
Tooth loss commonly accompanies a variety of oral diseases and physiological causes, including dental caries, periodontal disease, trauma, genetic disorders and aging, and can lead to physical and mental suffering that markedly lowers the individual’s quality of life2.
Keeping one’s own teeth throughout life is not only beneficial for enjoying food and maintaining quality of life, but also helps to prevent dementia as mastication stimulates brain3. Henceforth, tooth regeneration is of particular relevance to field of regenerative medicine4.
The current strategies to tissue replacement and reconstruction include the utilization of autogenous grafts, allografts  and synthetic materials, but each of them has limitations, which may include lack of significant stores for excess tissue transplantation, possibility of eliciting an immunologic response due to genetic differences or inducing transmissible diseases1.
The gold standard to replace an individual’s  lost or damaged tissues is the one made from patient’s own tissue and grown in its intended location5. This standard has also lead to the concept of engineering or regenerating new tissue from pre existing tissue.
Tissue engineering is a multidisciplinary field which applies the principles of life science, engineering and basic science to the development of viable substitutes which restore, maintain or improve the function of human tissues. Modern isolation and culturing technique of any types of human cells provides the basis of tissue engineering. Naturally derived or synthetic biomaterials are fashioned into scaffolds, which when cultured and implanted in combination with cells, provide a template that allows such constructs to form new soft and hard tissues, during which time the scaffold degrades and is finally metabolized6.


STRATEGIES TO ENGINEER TOOTH
Currently, there are two major approaches to tooth regeneration. The first is based on tissue engineering and aims to regenerate teeth by seeding cells on scaffolding biomaterials 7,8. This technique has already been applied to the regeneration of periodontium and holds great future promise for predictable periodontal regeneration9. The second approach involves reproducing the developmental processes of embryonic tooth formation and this requires an understanding of the basic principles that regulate early tooth development and uses embryonic tissues (dental epithelium and dental mesenchyme) harvested from a mouse fetus10. Artificial tooth germs bioengineered through both approaches are transplanted into the bodies of animal hosts, where there is sufficient blood flow to provide the necessary nutrients and oxygen for tissue formation2.


TOOTH REGENERATION USING TISSUE ENGINEERING
In the late 1980’s, organ transplant surgeon Joseph P. Vacanti of Harward Medical School and polymer chemist Robert S. Langer of  the  Massachusetts Institute of Technology conceived the idea of placing the cells of an organ or tissue on a prefabricated biodegradable scaffold with the goal of generating tissues and organs for transplantation.
The approach is based on the fact that living tissues are made of cells constantly signaling to one another and often moving around within a three dimensional community of sorts. Each cell knows its place and role in the larger collective. Therefore, if the right mix of dissociated cells is reaggregated with a scaffold that replicates their natural 3-D environment, the cells should instinctively reform the tissue or organ to which they belong. 5
Vacanti and Langer’s successful technique of bioengineering neonatal intestine11 and stomach using the scaffold based strategy has led to experimentation to produce other complex tissues like heart muscle, intestine, mineralised bone and teeth by Pamela C. Yelick and John D. Bartlett of Forsyth Institute in Boston.11
Yelick’s group enzymatically dissolved dental epithelial and pulpal mesenchymal tissues form the unerupted third molars of a six month old pig10 and seeded the mixture of the heterogeneous single cells onto a tooth shaped biodegradable polymer scaffold constituting of polyglycolic acid (PGA) and poly-co-glycolide copolymer (PLGA).The cells, scaffolds constructs were implanted into the intestine of rat hosts to receive sufficient blood supply, nutrients and oxygen. By 2-30 weeks, after the implantation, tiny tooth like tissues (like enamel, dentin and pulp)7 were observed within the implants, which resembled the crowns of natural teeth, with rudimentary tooth root structures. Although most dental tissues were regenerated with cells from an adult source and scaffold materials, with success rate for achieving the correct arrangement of the natural tooth is only 15% -20%5. Further studies are therefore required to consistently achieve reconstituted and structurally sound teeth2.

Figure1.

TOOTH REGENERATION USING DEVELOPMENTAL APPROACH

Rather than attempting to build adult teeth from their constituent cells, Sharpe’s group replicated the natural processes involved in embryonic tooth development, focusing on the reciprocal interactions between the epithelium and mesenchyme10.Recombinations between mesenchyme created in vitro(by aggregation of non dental cultured cells from different  cell sources) and embryonic oral epithelium collected from mouse embryos at 10th embryonic day(E10) , stimulated an odontogenic response in the mesenchyme. When such explants were transferred intact into adult renal capsules, they developed into teeth (crowns) with associated bone and soft tissues5.
The results offer important insights into tooth development and suggest that stem cells derived from adult bone marrow can take place of dental mesenchyme2 and the odontogenic process can be initiated in non dental cells of different origins10. Bone and soft tissues can be formed from non dental cell populations consisting entirely of purified stem cells or from heterogeneous population such as bone marrow derived cells10. But no suitable source of epithelial components has yet been found to replace the embryonic oral epithelium2.
Many years of experiments have established that embryonic epithelium12 contains a unique set of signals for odontogenesis that disappear from the mouth after birth. Sharpe’s group is continuing to seek an effective population of substitute cells that could be derived from an adult source5.

The teeth obtained from Sharpe’s group were in the normal size range for mouse teeth and showed earliest signs of root formation. Though it was doubtable whether such explants could also form teeth in the mouth. In embryonic jaw, soft tissues, teeth and bone, all are developing together without external stresses such as chewing and talking, where as it was not the case in adult jaws.

Sharpe group extracted tooth buds from embryonic mice (E14.5), then transplanted them into the diastema pockets between molars and incisors of adult mice. The mice were fed on soft diet and the transplants were monitored.5 The decalcified sections of the diastema, clearly revealed ectopic tooth formed at the site of transplantation. The teeth were in correct orientation, of appropriate size and attached to underlying bone by soft connective tissue. Thus, adult mouth could provide a suitable environment for tooth development10.
These approaches to tooth reconstitution using developing tissues are far from ready for patient application because it would be impractical to use human embryonic tissue. Strategic improvements are needed prior to clinical application to prevent immune rejection and to overcome ethical issues.

Though identification of stem cells in dental pulp and from exfoliated deciduous teeth also raises the possibility that a patient’s own tooth cells could be used to generate new tooth primordia13.

FUTURE TRENDS
Although in its infancy, tissue engineering approach can be used to bioengineer highly mineralized, anatomically correct replacement tooth tissues, reflecting its need for alternative therapies to treat variety of dental repair needs14. It is eventually possible to device clinically relevant therapies to replace damaged or lost dental tissues with biologic dental materials as a viable alternative to synthetic dental materials.
The research also provides intermediate products that can be used to augment existing synthetic dental repair materials eg, it is possible to use bioengineered dental materials to improve the function and duration of currently used titanium implants to underlying alveolar bone via autologous bioengineered periodontal ligament would help transmit mechanical forces of mastication from implants  to underlying bone and might also help perform orthodontic treatments11.
Post natal stem cells isolated from developing wisdom teeth can regenerate functional tooth roots and periodontal ligaments that support synthetic crowns2.

We have entered an exciting era where the diverse fields of tissue engineering, material science, nano technology and stem cell biology have converged synergistically to provide unprecedented opportunities to characterize and manipulate signaling cascades, regulating tissue and organ regeneration.
The future for regenerative and tissue engineering applications to dentistry is one with immense potential, capable of bringing quantum advances in treatment for patients. The need for high quality research in the basic sciences is paramount to ensuring that the development of novel clinical treatment modalities is underpinned by robust mechanistic data and that such approaches are effective. This translational model epitomizes how dentistry should evolve and highlight the needs for close partnership between basic and clinical scientists.
Apart from the potential benefit to people who need new teeth, this research also offers two significant advantages for testing the concept of organ replacement15. Teeth are easily accessible and whereas our quality of life is greatly improved if we have them, we do not need our teeth to live. These may seem trivial points, but as the first wave of replacement organs start to make their way towards the clinic, teeth will serve as a crucial test of feasibility of different tissue engineering techniques. With organs essential to life, doctors will have no leeway to make mistakes, but mistakes with teeth would not be life threatening and could be corrected.

CHALLENGES
Tooth regeneration has also identified certain challenges. First, there are limits to the traditional principles of tissue engineering, related to whole tooth regeneration with correct morphology. Secondly, adult bone marrow cells can though alternate dental mesenchymal cells but no suitable substitute for embryonic epithelial compartment has yet been recognized.

Moreover, the techniques have not yet been established to control tooth size, shape and colour, particularly full human tooth size. Problems concerning the cell numbers obtained, host immune rejection and ethical issues of the use of human embryos still remains. Relevant ethical issues include the source of cells (patient’s own vs donated cells) and type (adult donor vs fetal cells).

CONCLUSION
The control of morphogenesis and cytodifferentiation is a challenge that necessitates a thorough understanding of the cellular and molecular events involved in development, repair and regeneration of teeth. The identification of several types of epithelial and mesenchymal stem cells in the tooth and the knowledge of molecules involved in stem cell fate is a significant achievement. Though, many problems remain to be addressed before considering the clinical use of  these technologies. The use of animal cells for human diseases is restricted by immune rejection risks. It is possible to replace dental mesenchymal stem cells with stem cells of another origin, but not so is the case with epithelial stem cells.
A reliable source of epithelial stem cells remains to be determined. Alternative solutions such as use of artificial crowns are considered. The engineering of tridimensional matrices (either PLA polymers or collagen sponge) with a composition more or less similar to that of  the organs to reconstruct and the addition of growth factors such as FGF or BMP might facilitate transplantation and differentiation of stem cells. However, engineering of tooth substitutes is hard to scale up, costly, time consuming and incompatible with the treatment of extensive tooth loss.
The field of tooth tissue engineering is one of the many areas likely to see significant progress in the next decade.

REFERENCES

  1. Kaigler Darnell, Mooney David. Tissue engineering’s impact on dentistry: Journal of Dental Education 2001;65(5):456-462
  2. Nakahara T, Yoshiaki DE. Tooth regeneration: Implications for the use of bioengineered organs in first wave organ replacement. Human Cell 2007;20:63-70
  3. www.sciencedaily.com/releases/2007/10/071010111807.htm
  4. Smith AJ. Tooth tissue engineering and regeneration: a Translational vision! J  Dent Res 2004;83:517
  5. Sharpe PT, Young CS. Test tube teeth.  Sci Am 2005;293:34-41
  6. http://www.lumrix.net/medical/bioengineering/tissue_engineering.html
  7. Young CS, Terada S, Vacanti JP, Yelick PC. Tissue engineering of complex tooth structures on biodegradable polymer scaffolds. J Dent Res 2002;81:695-700
  8. Duailibi MT, Duailibi SE ,Young CS, Bartlett JD, Vacanti JP, Yelick PC. Bioengineered teeth from cultured rat tooth bud cells. J Dent Res 2004;83:523-28
  9. Nakahara T.A review of new developments in tissue engineering therapy for periodontics. Dent Clin North Am 2006;50:265-76
  10. Ohazama A, Modino SA, Miletich I, Sharpe PT. Stem cell based tissue engineering in murine teeth.J Dent Res 2004;83:518-22

References are available on request

Authors: Dr. Pankaj Agarwal(Senior Lecturer), Dr. Umesh Chandra Prasad (Professor), Dr. Ramballabh (Senior Lecturer), Dr. Juhi (Senior Lecturer),

Abstract
Intraoral pigmentation is quite common and has numerous etiologies, ranging from exogenous to physiological to neoplastic. Many pigmented lesions of the oral cavity are associated with melanin pigment. The differential diagnosis of mucosal pigmented lesions includes hematomas, varices, and petechiae which may appear to be pigmented. Unlike cutaneous melanomas, oral melanomas are diagnosed late and have a poor prognosis regardless of depth of invasion. As such, the clinical presentation and treatment of intraoral melanoma will be discussed. Developing a differential diagnosis is imperative for a clinician faced with these lesions in order to appropriately treat the patient. This article will focus on the most common oral melanocytic lesions, along with mimics.

KEYWORDS: melanin, melanotic macule, oral melanoma

Introduction

Oral pigmentation is quite common, and its differential diagnosis is broad. The pigmentation can be the result of exogenous factors such as embedded foreign material including tattoo pigment, amalgam from dental restorations, or pencil lead. Endogenous pigmentation can be associated with numerous physiological conditions and syndromes, including Addison’s disease, Peutz-Jeghers syndrome, Laugier–Hunziker syndrome, and rarely neurofibromatosis type 1.1,3 Other endogenous sources of pigmentation can include hemoglobin, hemosiderin, and bilirubin. Post- inflammatory pigmentation can result from chronic trauma (e.g., cheek biting) or inflammation (e.g., erosive oral lichen planus). Tobacco use can cause smoker’s melanosis.4 A variety of systemic medications including antimalarials such as chloroquine, estrogen, and zidovudine have also been associated with oral pigmentation.1,5 Minocycline pigmentation in almost all cases involves the bone and teeth rather than the mucosa.6,8 Although uncommon, acquired melanocytic nevi, including junctional, compound, intramucosal, and blue nevi, can present in the oral cavity..9, 10
Melanocytes present in the basal cell layer of the oral mucosa are similar to those found in the skin. The melanocytes synthesize melanin that is then transferred to the epithelial cells, as well as to macrophages (melanophages). Incontinent melanin pigment can often be noted, particularly in the superficial lamina propria. The color of mucosal pigmentation can vary from brown to blue to black depending on the depth of the pigment within the mucosa (Tyndall effect).
Because of the varied appearance of oral pigmented lesions, diagnosis cannot always be reliably made by clinical examination alone. Clinicians should therefore have a low threshold to biopsy these important lesions. This review will focus on developing a differential diagnosis for the most common melanin-pigmented lesions of the oral mucosa.
Physiological pigmentation
Physiological pigmentation is common and results not from an increase in melanocyte number, but rather greater melanocytic activity. 1. Darker- skinned individuals are more commonly affected.
The color of physiological pigmentation can range from light brown to almost black. Physiological pigmentation increases with age, and color intensity can be influenced by smoking, hormones, and systemic medications.2The attached gingiva is the most common location, but physiological pigmentation can be noted anywhere in the oral cavity, including the tips of the fungiform papillae on the dorsal tongue.

The diagnosis of physiological pigmentation can be made clinically, and no treatment is necessary unless for cosmetic concerns. The use of lasers such as erbium-YAG laser has been reported to effectively remove oral pigmentation, including physiological pigmentation.
A biopsy of physiological pigmentation will show no increase in the number or upward migration of melanocytes. It will demonstrate increased melanin pigmentation of the basal layer, as well as occasional incontinent melanin and/or melanophages in the superficial lamina propria (connective tissue just beneath the epithelium). These microscopic features are similar to those seen in oral melanotic macule. The clinical differential is based on diffuse versus focal pigmentation.

Amalgam tattoo

Inadvertent implantation of dental amalgam is one of the most common etiologies of intraoral pigmentation and may be mistaken for a melanocytic lesion. 1,9,14 Amalgam tattoos are painless; gray- blue macules that range in size from a few millimeters to greater than 1 cm. The tattoo can be single or multiple. Most amalgam tattoos are located on the gingiva and edentulous mucosa, but can also be seen on the hard palate, buccal mucosa, and floor of the mouth. Radiographic evaluation may be positive. When mucosal pigment exhibits a blue-gray color in a patient that reports a history of dental amalgam restorations of either primary deciduous or permanent dentition, a biopsy may be unnecessary. However, if either of these criteria is not met, a biopsy is indicated. On histological examination, fine black granular or fibrillar material embedded in the connective tissue or in a perivascular location with little or no inflammatory response is seen. Foreign body giant cell reactions are uncommon.

The differential diagnosis of amalgam tattoo includes graphite/lead tattoo, implantation of other foreign material, and post-inflammatory pigmentation.

Smoker’s melanosis

Smoker’s melanosis is a phenomenon of increased melanin pigmentation seen in heavy smokers, most commonly cigarette smokers4Smoker’s melanosis is more common in women, suggesting that estrogen may play a role. This pigmentation is thought to be caused by increased melanin production in response to heat or exposure to tobacco smoke. The increased melanin is postulated to have a protective effect against the harmful components of tobacco smoke.1 The most common location of smoker’s melanosis is the labial gingiva, although any oral site can be affected.
Smoker’s melanosis seen in pipe smokers most often is noted on the buccal mucosa or the commissure of the lip along the vermilion border. Diagnosis is made by correlating the clinical findings with the patient’s smoking history. Other diagnostic considerations include physiological pigmentation; systemic causes of oral melanosis such as Addison’s disease, Peutz–Jeghers syndrome, and hemochromatosis; or drug. The microscopic features are similar to those described for physiological pigmentation.

Oral melanotic macule

The oral melanotic macule, also known as focal melanosis, is a benign, mucosal macule uniformly tan to dark brown in color less than 1 cm in size.15 Although generally solitary, multiple lesions have been reported. The color is typically a result of increased melanin deposition, although there may also be an increase in the number of melanocytes. The melanotic macule is not dependent on solar exposure. Although the lower lip is the most common site of occurrence (33%), other intraoral sites include the buccal mucosa, gingiva, and palate. Oral melanotic macules occur in a wide age range with a 2: 1 female predominance. They can occur in Caucasians, as well as darker-skinned patients. Buccal mucosa lesions may occur more frequently in blacks.1

The diagnosis rests on both the clinical presentation of a solitary lesion along with the microscopic features, because the pathology is not specific. On microscopic examination, increased melanin deposition predominantly in the basal cell layer is demonstrated. The epithelium otherwise is of normal stratified squamous epithelium without atypia or elongated rete pegs. Incontinent melanin pigment and melanophages may be noted in the superficial lamina propria.
Generally, oral melanotic macules do not require treatment unless for aesthetic concerns. There are no reports of malignant transformation to melanoma. A biopsy should be performed on melanotic macules that exhibit recent onset, increased size, or irregular pigmentation. Because the palate is the most common site for intraoral melanoma, complete removal of all palatal pigmented lesions is recommended.11,12

Oral melanoacanthoma
Oral melanoacanthoma is an uncommon benign pigmented tumor of the oral mucosa most commonly seen in black women in the third to fourth decades. The buccal mucosa is the most common location, but involvement of the lips, palate, and gingiva has also been reported. The color can range from brown to almost black. Most lesions are solitary and asymptomatic; however, burning and pain have been reported. This lesion is remarkable for rapid increase in size to several centimeters. The etiology of oral melanoacanthoma is not understood; however, trauma has been reported to be a factor in some cases.12,16,17Despite the large size, many cases resolve without treatment or after biopsy. A biopsy to rule out melanoma is indicated because of the worrisome appearance of a rapidly growing, darkly pigmented lesion.

Oral melanoacanthoma microscopically exhibits acanthosis and spongiosis of the epithelium.Dendritic melanocytes that are normally confined to the basal layer are instead dispersed throughout the epithelium and can be highlighted with S100 immunohistochemistry.16 A mild inflammatory cell infiltrate can be seen in the superficial lamina propria.

Melanocytic nevi
Intraoral melanocytic nevi are uncommon and present on the hard palate, gingiva, buccal mucosa, and lip as painless, pigmented macules or papules that range in color from brown to black or blue.12 Most intraoral melanocytic nevi are thought to be acquired rather than congenital.12,18,19 Unlike mature cutaneous nevi which often have a  papillary surface, oral nevi are smooth. In a series of 130 cases of oral nevi from California, the average age at diagnosis was 35 years (range 3–85) with a 1.5: 1 female: male ratio.19In one series from The Netherlands, the annual incidence was 4.35 cases per 10 million persons.18 The differential diagnosis of intraoral nevi includes melanotic macule, physiological pigmentation, amalgam tattoo, and melanoma.19 Approximately 15% of intraoral nevi are amelanotic and present as a solitary sessile mucosal-colored lesion that can be mistaken for a fibroma.12,18
Intraoral nevi have similar histological classification schemes as their cutaneous counterparts: junctional, compound, and intramucosal. In junctional nevi, there is a proliferation of benign melanocytes along the basal cell layer. In compound nevi, benign neoplastic melanocytes are found in the basal cell layer and in the superficial lamina propria. In intramucosal nevi, the nevo melanocytes are located in the lamina propria without a junctional component. The most common oral nevi are intramucosal nevi, which may reflect the age of the patient at the time of biopsy. Intraoral dysplastic nevi have not been reported.1
There are no reports of malignant transformation of intraoral nevi even in patients who have had mutiple nevi or congenital nevi. Biopsy is advisable for any new oral pigmentation because an early melanoma may be mistaken for a melanocytic nevus.
The blue nevus is the second most common type of intraoral nevus, present as a small, less than 1 cm, blue-black macule or dome-shaped papule most commonly on the palate.19Blue nevi are more common in women and are noted usually in the second to fourth decades, although congenital blue nevi have been reported. Malignant transformation of an oral blue nevus to melanoma has not been documented.
On microscopic examination, spindled-shaped melanocytes with abundant melanin pigment are seen deep in the lamina propria, arranged in a parallel fashion to the overlying epithelium. A combined nevus showing histological features of both a blue nevus and a melanocytic nevus can also be seen.20

Intraoral melanoma
Primary mucosal melanoma of the oral cavity is extremely rare accounting for less than 1% of all melanomas.21 The incidence of oral mucosal melanoma is relatively stable. In the head and neck areas, the most common sites for mucosal malignant melanoma are the sinonasal and oral mucosae. Within the oral cavity, the palate is the most common site.12 In a 20-year review of the surgical pathology files in the Department of Pathology at our institution, only eight cases of primary oral melanoma were diagnosed compared to 22 cases of sinonasal melanoma.11 The palate and maxillary alveolus accounted for all these cases.11 To date, no precursor lesion is known for intraoral melanoma, although a prior history of pigmentation in the area of the tumor has been noted in about one-third of patients.12

Biopsies of these pigmented areas often show atypical melanocytic hyperplasia.1,22 Oral Malignant melanoma is seen in the sixth to seventh decades, and a male: female ratio of 2.5,3: 1 is noted.12 Patients often present at an advanced stage with pain, mobile teeth, and bone involvement. Nodal metastases at the time of diagnosis have been reported in more than 50% of cases.23

The most common growth patterns noted are acral lentiginous and/or nodular patterns.22 Rarely, amelanotic melanoma can be seen intraorally presenting as a mass that has ill-defined borders and may appear erythematous.12 Histologically,amelanotic melanomas may demonstrate pigmentation.

Microscopically, intraoral melanoma can demonstrate areas of radial growth phase typical of a superficial spreading melanoma similar to acral lentiginous melanoma. Pagetoid spread with large melanoma cells either singly or in nests may be seen in the superficial epithelium. Nodular melanoma is the other most common pattern of intraoral melanoma and is often noted early in tumor development. When intraoral melanoma is diagnosed at an advanced stage, the associated radial growth phase is often absent. In nodular malignant melanoma, the malignant melanocytes typically will have an epithelioid or spindle-shaped appearance containing fine melanin granules. Bone and/or cartilage invasion can be seen in 35% of cases, whereas vascular invasion is not a common finding. 11 When intraoral melanoma presents with an acral lentiginous or nodular growth pattern with abundant melanin pigment, the diagnosis is usually not difficult. Independent of histological suspicion, immunohistochemistry studies such as HMB45, S100, melanA, or MitF are necessary for definitive diagnosis.

Once a diagnosis of oral melanoma is made, appropriate imaging of patients may include a positron emission tomography (PET) for the evaluation of metastatic disease along with computed tomography (CT) to evaluate the primary tumor and cervical lymph nodes. In patients with extensive metal dental restorations, magnetic resonance imaging may be preferable to CT because of artifactual streaking.

The mainstay of treatment for oral melanoma is surgical excision. Clear margins are not always possible because of the anatomical and functional considerations of this region.11,23With regard to the management of the clinically and radiographically negative neck, some centers advocate prophylactic cervical lymph node dissection because of the high rate of metastases.23 Both radiation and immunotherapy have been used in the treatment of oral melanoma particularly in patients with a strong likelihood of local or regional recurrence. The use of adjuvant chemotherapy and/or immunotherapy in oral melanoma has been extrapolated from cutaneous melanoma data.

These are not advocated as monotherapy because they do not improve overall survival. Despite all available treatments, oral melanoma has a poor prognosis with a 10–20% 5-year survival rate.11,19,23 This poor survival rate is a result of the difficulty in obtaining wide surgical margins of excision as mentioned above, as well as early hematogenous spread. Many intraoral melanoma patients develop widespread metastases to lung, liver, brain, as well as lymph nodes.

The parotid gland is also a site of cutaneous melanoma metastasis because of its numerous intra- and periparotid lymph nodes which are primary sites of lymphatic drainage from auricle, cheek, parietal scalp, and forehead skin. Parotid swelling in a patient with a cutaneous malignancy of the head and neck should be investigated for metastases. Often, these lesions are amenable to fine-needle aspiration to obtain a tissue diagnosis.CT scans are also helpful in the evaluation.

Conclusion

When a patient presents with intraoral pigmentation, a thorough medical and dental history, along with extraoral and intraoral examinations, should be undertaken. Important information includes size, color, onset, and duration of the lesion(s) in addition to any localized or systemic symptoms. Smoking history and medication history should be included. Many pigmented lesions can be clinically diagnosed based on size, shape, or color, along with the clinical information. However, pigmented lesions that have increased in size or that cannot be explained by local factors, such as an amalgam tattoo, require biopsy to establish a diagnosis.

References:-

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  20. Ficarra G, Hansen LS, Engebretsen S, Levin LS. Combined nevi of the oral mucosa. Oral Surg Oral Med Oral Pathol 1987: 63 (2): 196–201.
  21. McLaughlin CC, Wu XC, Jemal A, Martin HJ, Roche LM,Chen VW. Incidence of noncutaneous melanomas in the U.S. Cancer 2005: 103: 1000–1007.
  22. Barker BF, Carpenter WM, Daniels TE, et al. Oral mucosal melanomas: The WESTOP Banff workshop proceedings. Oral Surg Oral Med Oral Pathol Oral Radiol Endod 1997: 83:672–679.
  23. Mendenhall WM, Amdur RJ, Hinerman RW,Werning JW, Villaret DB, Mendenhall NP. Head and neck mucosal melanoma. Am J Clin Oncol 2005: 28: 626–630.
Authors Dr. Jagadish V. Hosmani, Dr. Deepa Hugar, Dr. Ramakant S. Nayak

Abstract:
A case of a dentigerous cyst with sebaceous glands differentiation seen at the interface between the epithelium and connective tissue in a 13 year old female patient is reported here.

Introduction
Jaw cysts with sebaceous elements are rare and various interpretations of such cysts have been given in the literature. Some authors have preferred to consider these lesions as intraosseous dermoid cysts due to the virtue of sebaceous glands being dermal adnexal structures.1 Hofrath, Gorlin, and Spouge documented the occurrence of sebaceous glands in dentigerous cyst. 2,3,4 Here we report a case of dentigerous cyst with sebaceous differentiation in a 13 year old female.

Case History
A female patient aged 13 years reported to our institution with the chief complaint of a painless swelling in the lower left posterior tooth region since 6 months. Extraoral examination revealed slight facial asymmetry. Intraoral examination revealed single, lobulated, intraosseous swelling with obliteration of buccal vestibule with respect to primary mandibular second molar region. On palpation the swelling was firm and non tender. Primary mandibular second molar was carious and was grossly destructed.
Radiological examination by OPG revealed grossly decayed primary mandibular second molar showing resorption of roots. Well defined unilocular radiolucency around the crown of impacted mandibular second premolar was seen. The radiolucency extended from the distal surface of root of first premolar to the mesial surface of root of first permanent molar. Radiologically the lesion mimicked to be radicular cyst associated with primary mandibular second molar. (Figure 1)
A provisional diagnosis of dentigerous cyst was made. All routine lab investigations followed by FNAC were done. Red colored fluid was drawn. FNAC smear revealed sheets of RBCs and neurtrophils. Patient was referred to oral surgery where the lesion was surgically excised and specimen was subjected for histopathological examination.
Microscopically, the lesion showed 3-4 layered non keratinized stratified squamous epithelium with focal areas of hyperplasia. The underlying connective tissue was inflamed characterized by diffuse infiltration of lymphocytes, plasma cells and macrophages. Focal sebaceous cells were identified in association with the connective tissue. (Figure 2 & 3)
A diagnosis of infected dentigerous cyst with sebaceous differentiation within the connective tissue was given.

Discussion:
Sebaceous glands are holocrine glands that produce an oily product called sebum. Normal sebaceous glands typically are found in conjunction with hair follicles as part of a pilosebaceous unit. Therefore, the distribution of normal sebaceous glands roughly corresponds to that of hair that is, widely distributed throughout the skin. 4,5 Within the oral cavity, sebaceous glands may present as small, subtle, yellowish spots called Fordyce granules, which exhibit a predilection for the buccal mucosa. Estimated to occur in more than 80% of the population,6 Fordyce granules are such a frequent finding that they can be considered a normal anatomic variation rather than an ectopic phenomenon.7 In addition, aberrant or ectopic sebaceous glands have been described in various locations, including the parotid gland, orbit, larynx, and esophagus. Proposed theories to explain the occurrence of aberrant or ectopic sebaceous glands include development from sequestered multipotent epithelial cells and metaplasia of existing mature epithelium.4

Intraosseous jaw cysts with sebaceous elements are rare, and various interpretations of such cysts have been given in the literature. Some authors have described these lesions as orthokeratinized odontogenic cysts (OOCs) exhibiting sebaceous differentiation, whereas others have preferred to consider these lesions intraosseous dermoid cysts or unusual variants of dentigerous cysts.1 Chi et al reported 5 cases of jaw cysts with sebaceous elements and reviewed the literature concerning these unusual lesions. In particular they examined the apparent controversy as to whether these lesions are best considered odontogenic or nonodontogenic in origin. In the jaw cysts which the authors reviewed many were interpreted to represent odontogenic cyst with sebaceous elements formed by metaplasia of the epithelial lining. Whereas sebaceous glands located deeper within the cyst wall potentially could originate from metaplasia of sequestered epithelial rests.1
Other authors have interpreted intraosseous jaw cysts with sebaceous glands as dermoid cysts and have rejected theories of odontogenic origin.1 Dermoid cysts commonly occur in soft tissues and reports of intraosseous dermoid cysts of the jaw are exceedingly rare.8 Characteristic microscopic features of the dermoid cyst include an epidermis like lining, intraluminal keratinaceous debris, and one or more skin appendages. The presence of hair follicles and/ or sweat glands could be considered evidence in favor of an epidermal rather than odontogenic origin of such cysts. On the other hand, if it is possible for sebaceous differentiation to occur in odontogenic cyst, then perhaps it is possible for odontogenic cyst to exhibit the formation of hair follicles or sweat glands as well.8 Many investigators have commented on the pluripotentiality of the odontogenic epithelium, which apparently may have the capacity to differentiate into sebaceous cells, mucous cells, respiratory epithelial cells, and other cell types. But well formed adenexal structures other than sebaceous glands arising from odontogenic epithelium have not been conclusively demonstrated.3, 9
It seems reasonable to postulate that some factors in the oral mesenchyme could interact with epithelium of almost any source to produce wide variability in structure and potential of the affected epithelium. The multipotentiality of the oral epithelium may be secondary to the influence of the mesenchyme, resulting in the differentiation of sebaceous glands in odontogenic cysts. 10

In our case presented here adnexal structures other than sebaceous gland was absent in the lining epithelium and connective tissue. Thus we believe that the lesion is odontogenic in origin and we can exclude dermoid cyst. Some authors have preferred to use more descriptive, noncommittal terminology for these lesions, such as “intraosseous mandibular cyst with sebaceous differentiation”, as proposed by Cristensen and Propper.
To summarize, it is important to note that dentigerous cyst with sebaceous differentiation do occur and must be separated from other non odontogenic cysts in a clinical and histological differential diagnosis.
Figure Legends
Figure 1: Orthopantomograph showing well defined unilocular radiolucency around the crown of impacted left mandibular second premolar. Figure 2: Photomicrograph showing typical cystic lining of dentigerous cyst having 2-3 layered non keratinized epithelial lining. Focal collection of sebaceous elements is seen in the underlying connective tissue. (Hematoxylin & Eosin, X 40) Figure 3: Photomicrograph showing sebaceous cells as well as chronic inflammatory cells within the connective tissue. (Hematoxylin & Eosin, X 100)
References
  1. Chi AC, Neville BW, McDonald TA, Trayham RT, Byram J, Peacock EH. Jaw cysts with sebaceous differentiation: report of 5 cases and a review of the literature. J Oral Maxillofac Surg 2007; 65: 2568-2574
  2. Hofrath H. Uber das vorkommen Von Talgdrussen in der Wandung einer Zahncyste, Zugelich ein Beitrag zur Pathogenese der kiefer-Zahncysten, Dtsch Monatsschr. Zahn heilkd. 1930; 2:65-76.
  3. Gorlin RJ. Potentialities of oral epithelium manifested by mandibular dentigerous cyst. Oral Surg 1957; 10:271-84.
  4. Spouge JD. Sebaceous metaplasia in the oral cavity occurring in association with dentigerous cyst epithelium. Oral Surg 1966; 21: 492-8.
  5. Downie MMT, Guy R, Kealey T. Advances in sebaceous gland research: Potential new approaches to acne management. Int J Cosmet Sci 2004; 26: 291
  6. Halperin V, Kolas SR, Huddleston So, Robinson Hb. The occurrence of Fordyce spots, benign migratory glossitis, median rhomboid glossitis, and fissured tongue in 2,478 dental patients. Oral Surg Oral Med Oral Pathol. 1953 Sep; 6(9):1072-7.
  7. Neville BW, Damm DD, Allen CM. Fordyces Granules, in Oral & Maxillofacial Pathology (ed 2). Philadelphia, WB Saunders, 2002, p6.
  8. Neville BW, Damm DD, Allen CM. Fordyces Granules, in Oral & Maxillofacial Pathology (ed 2). Philadelphia, WB Saunders, 2002, p32.
  9. Brannon RB. The odontogenic keratocyst: A clinicopathologic study of 312 cases. Part II. Histologic features. Oral Surg Oral Med Oral Pathol 1977; 43: 233.
  10. Shamim T, Varghese I, Shameena PM, Sudha S. Sebaceous differentiation in odontogenic keratocyst. Indian J Pathol Microbiol 2008; 51(1): 83-84.
Authors: Dr. Jagadish V. Hosmani(Senior Lecturer), Dr. Deepa Hugar (Senior Lecturer), Dr. Ramakant Nayak, (Professor & H.O.D.)

The World Health Organization has clearly indentified prevention and early detection as major objectives in the control of the oral cancer burden worldwide. At the present time, screening of oral cancer and its pre-invasive intra-epithelial stages, as well as its early detection, is still largely based on visual examination of the mouth. There is strong available evidence to suggest that visual inspection of the oral mucosa is effective in reducing mortality from oral cancer in individuals exposed to risk factors. Simple visual examination, however, is well known to be limited by subjective interpretation and by the potential, albeit rare, occurrence of dysplasia and early OSCC within areas of normal-looking oral mucosa. As a consequence, adjunctive techniques have been suggested to increase our ability to differentiate between benign abnormalities and dysplastic/malignant changes as well as to identify areas of dysplasia/early OSCC that are not visible to naked eye.

In the past decades, adjunctive techniques have emerged with claims of enhancing oral mucosal examinations and facilitating the detection of and distinctions between oral benign and oral premalignant and malignant lesions . Clinicians who use these tools may be unaware of the state of the evidence supporting their effectiveness. Techniques that are promoted or assessed to improve earlier detection and diagnosis of oral malignancy include toluidine blue , ViziLite Plus with TBlue , ViziLite , Microlux DL , Orascoptic DK ,VELscope and OralCDx brush biopsy.In developing countries such as India, where there is a high prevalence of disease, the focus is on downstaging oral cancer at diagnosis from advanced to earlier disease. In the United States, by contrast,these adjunctive techniques are marketed to facilitate the detection of premalignant disease. It is assumed that if a premalignant lesion is detected and treated, the lesion may not progress to cancer.
The World Health Organization has clearly indentified prevention and early detection as major objectives in the control of the oral cancer burden worldwide. At the present time, screening of oral cancer and its pre-invasive intra-epithelial stages, as well as its early detection, is still largely based on visual examination of the mouth. There is strong available evidence to suggest that visual inspection of the oral mucosa is effective in reducing mortality from oral cancer in individuals exposed to risk factors. Simple visual examination, however, is well known to be limited by subjective interpretation and by the potential, albeit rare, occurrence of dysplasia and early OSCC within areas of normal-looking oral mucosa. As a consequence, adjunctive techniques have been suggested to increase our ability to differentiate between benign abnormalities and dysplastic/malignant changes as well as to identify areas of dysplasia/early OSCC that are not visible to naked eye.

In the past decades, adjunctive techniques have emerged with claims of enhancing oral mucosal examinations and facilitating the detection of and distinctions between oral benign and oral premalignant and malignant lesions . Clinicians who use these tools may be unaware of the state of the evidence supporting their effectiveness. Techniques that are promoted or assessed to improve earlier detection and diagnosis of oral malignancy include toluidine blue , ViziLite Plus with TBlue , ViziLite , Microlux DL , Orascoptic DK ,VELscope and OralCDx brush biopsy.In developing countries such as India, where there is a high prevalence of disease, the focus is on downstaging oral cancer at diagnosis from advanced to earlier disease. In the United States, by contrast,these adjunctive techniques are marketed to facilitate the detection of premalignant disease. It is assumed that if a premalignant lesion is detected and treated, the lesion may not progress to cancer.

THE DETECTION TECHNIQUES
Vital tissue staining. Tolonium chloride, more commonly referred to as TB, has been used for more than 40 years to aid in detection of mucosal abnormalities of the cervix and the oral cavity.TB is a metachromatic vital dye that may bind preferentially to tissues undergoing rapid cell division (such as inflammatory, regenerative and neoplastic tissue), to sites of DNA change associated with OPML or both. The binding results in the staining of abnormal tissue in contrast to adjacent normal mucosa. Toluidine blue (TB), also known as tolonium chloride, is a vital dye that is believed to stain nucleic acids.

Hence, it has been used for many years as an aid to the identification of clinically occult mucosal abnormalities and as a useful way of demarcating the extent of a potentially malignant lesion prior to excision . Several studies on TB have been performed in the past years but the majority of them present significant limitations and methodological biases . Analysis of current evidence suggests that TB is good at detecting carcinomas, but its sensitivity in detecting dysplasias is significantly lower . Furthermore, there remain a high percentage of false positive stains which impairs its use in primary care settings as a valid screening mean . In addition, controversy exists regarding the subjective interpretation of mucosal staining and criteria for positive results (e.g. dark royal blue versus pale blue staining). Visualization adjuncts. Several visualization adjuncts, described below, are intended for use as adjuncts to the standard visual and tactile oral examination under incandescent light. They function under the assumption that mucosal tissues undergoing abnormal metabolic or structural changes have different absorbance and reflectance profiles when exposed to various forms of light or energy.

Described as a chemiluminescent light detection system, ViziLite was developed from predicate devices to detect cervical neoplasia. Clinical inspection of oral mucosa with the aid of chemiluminescent blue/white light was recently suggested to improve the identification of mucosal abnormalities with respect to the use of normal incandescent light The relevant technology involves the use of an oral rinse with a 1% acetic acid solution for 1 minute followed by the examination of the oral mucosa under diffuse chemiluminescent blue/white light (wavelength of 490 to 510 nm). The theory behind this technique is that the acetic acid removes the glycoprotein barrier and slightly desiccates the oral mucosa, the abnormal cells of the mucosa then absorbing and reflecting the blue/white light in a different way with respect to normal cells. Hence normal mucosa appears blue, whereas abnormal mucosal areas reflect the light (due to higher nuclear/cytoplasmic ratio of epithelial cells) and appear more acetowhite with brighter, sharper and more distinct margins.More recently, the ViziLite system was modified in order to include the use of TB and a new chemiluminescence device (MicroLux DL) was introduced.

Several studies have been performed with the Vizilite system with the attempt to demonstrate its efficacy in to enhance the identification of mucosal abnormalities. It should be highlighted that no study has demonstrated that the chemiluminescence can help in differentiating dysplasia/carcinoma from benign lesions . Hence, the majority of studies have investigated how chemiluminescence enhances subjective clinical evaluation of intra-oral lesions including brightness, sharpness and texture with respect to routine clinical examination. As these parameters are highly subjective, it is not surprising that results have been contradictory . Whilst some authors report that this technique can improve the detection of intra-oral abnormalities (regardless their nature), other reports suggest that the overall detection rate was not significantly improved and the chemilumi nescent light produced reflections that made visualization even more difficult than with incandescent light Furthermore, the majority of the studies are limited by methodological flaws such as lack of histopathological diagnosis or clear objectives (screening device versus case-finding device) . Some studies suggest that chemiluminescence may help identifying occult lesions that cannot be seen with incandescent light but this, however, is not supported by any strong evidence.

Tissue Fluorescence Imaging

Tissue autofluorescence has been used in the screening and diagnosis of precancers and early cancer of the lung, uterine cervix, skin and, more recently, of the oral cavity. The concept behind tissue autoflorescence is that changes in the structure (e.g., hyperkeratosis, hyperchromatin and increased cellular/nuclear pleomorphism) and metabolism (e.g. concentration of flavin adenine dinucleotide [FAD] and nicotinamide adenine dinucleotide [NADH]) of the epithelium, as well as changes of the subepithelial stroma (e.g. composition of collagen matrix and elastin), alter their interaction with light . Specifically, these epithelial and stromal changes can alter the distribution of tissue fluorophores and as a consequencethe way they emit fluorescence after stimulation with intense blue excitation (400 to 460 nm) light, a process defined autoflorescence. The autoflorescence signal is finally visualized directly by a human observer. With regards to the oral cavity, normal oral mucosa emits a pale green autofluorescence when viewed through the instrument handpiece whilst abnormal tissue exhibits decreased autofluorescence and appears darker with respect to the surrounding healthy tissue. Autoflorescence technology for inspection of the oral mucosa has been developed by LED Medical Diagnostics Inc. in partnership with the British Columbia Cancer Agency and is marketed as VELscope system. Effectiveness of the VELscope system as an adjunct to visual examination for(i) improving the distinction between between normal and abnormal tissues (both benign and malignant malignant changes), (ii) differentiating between benign and dysplatic/malignant changes, (iii) and identifying dysplastic/ malignant lesions (or lesion's margins) that are not visible to the naked eye under white light. Overall the quality of available studies is significantly higher than that of studies upon chemiluminescence and TB as the technology's sensitivity and specificity was compared to gold standard (histopathology) in all patients studied .With regard to the first aspect, autofluorescence imaging of the oral mucosa has been reported to possibly improve lesions' contrast and therefore increase the ability to distinguish between mucosal lesions and healthy mucosa, although further research on different patients population is needed . The ability of autofluorescence to differentiate between different lesion types has been investigated in a few studies and overall the technique seems to show high sensitivity, but low specificity. However, the VELscope system seems to be very promising due to its ability and effectiveness in identifying lesions and lesions' margins that are occult to visual examination under white light. Using histology as the gold standard, VELscope demonstrated high sensitivity and specificity in identifying areas of dysplasia and cancers that extended beyond the clinically evident tumors . A direct clinical application consists of assessing lesion margins in patients with potentially malignant oral disorders therefore improving surgical management .However, it should be highlighted that these results are from case series and case reports rather than clinical trials and that no published studies have assessed the VELscope system as a diagnostic adjunct in screening lower-risk populations (e.g. without a history of dysplasia/OSCC) or in patients seen by primary care providers.

Tissue Fluorescence Spectroscopy

In addition to visual autofluorescence, a technique called autofluorescence spectroscopy has been recently tested in oral oncology research . The autofluorescence spectroscopy system consists of a small optical fiber that produces various excitation wavelengths and a spectrograph that receives and records on a computer and analyzes, via a dedicated software, the spectra of reflected fluorescence from the tissue. This technique has the clear advantage of eliminating the subjective interpretation of tissue fluorescence changes. However, the downside is that more variables (e.g. combination of wavelengths, methodology of fluorescence analysis etc) have to be tested and considered and this has led to controversial and often unclear results. Overall, autofluorescence spectroscopy seems to be very accurate for distinguishing lesions from healthy oral mucosa, with high sensitivity and specificity, especially when malignant tumors are compared to healthy mucosa. However, the ability of the technique to distinguish and classify different types of lesion has been reported to be low. Moreover autofluorescence spectroscopy is for practical reasons not suitable to detect new lesions or to demarcate large lesions as the optical fiber can sample only a small mucosal area . This limits the use of spectroscopy to the evaluation of a well defined small mucosal lesion that has been already identified through visual inspection, with the attempt to clarify its benign or (pre)malignant nature. Further research is needed to support this clinical application of autofluorescence spectroscopy. After receiving application of acetic acid, sites of epithelial proliferation, having cells with altered nuclear structure, are purported to preferentially reflect the low energy blue-white light emitted by a device generating an “acetowhite” change. The ViziLite system no longer is available as a single product, but is a part of the ViziLite Plus withTBlue system .The Microlux DL system is a multiuse system developed from a blue-white light-emitting diode and a diffused fiber-optic light guide that generates a lowenergy blue light.The Orascoptic DK system is sold as a three-in one, battery-operated, hand-held LED instrument with an oral lesion screening instrument attachment that is used in concert with a mild acetic acid rinse promoted to improve visualization of oral lesions. The VELscope system is a multiuse device with a handheld scope through which the clinician can scan the mucosa visually for changes in tissue fluorescence. The proposed mechanism of tissue fluorescence is that mucosal tissues have a reflective and absorptive pattern based on naturally occurring fluorophores in the tissue. Tissue fluorescence in the oral cavity is variable and isaffected by structural changes, metabolic activity, the presence of hemoglobin in the tissue, vessel dilatation and, possibly, inflammation. This variability has not been defined. Exposure to blue light spectra (400-460 nanometers) may maximize a differential profile in areas undergoing neoplastic change in which a loss of fluorescence visualization is reported.

Cytopathology is the microscopic study of cell samples collected from mucosal surfaces (via smears, scrapings orlavage) or from internal sites via fine-needle aspiration. The oral brush biopsy, also known as OralCDx Brush Test system, consists of a method of collecting a trans-epithelial sample of cells from a mucosal lesion with representation of the superficial, intermediate and parabasal/basal layers of the epithelium .

This test was specifically designed to investigate mucosal abnormalities that would otherwise not be subjected to biopsy because of low-risk clinical features . A specially designed brush is the non-lacerational device used for epithelial cell collection and samples are eventually fixed onto a glass slide, stained with a modified Papanicolaou test and analyzed microscopically via a computer-based imaging system. Results are reported as "positive" or "atypical" when cellular morphology is highly suspicious for epithelial dysplasia or carcinoma or when abnormal epithelial changes are of uncertain diagnostic significance respectively. Results are defined as negative when no abnormalities can be found. The test is considered an intermediate diagnostic step as a scalpel biopsy must follow when an abnormal result is reported (atypical or positive). Biopsy. The gold standard diagnostic test for oral mucosal lesions that are suggestive of premalignancy or malignancy remains tissue biopsy and histopathological examination.

The World Health Organization has clearly indentified prevention and early detection as the major targets in thebattle to control the oral cancer burden worldwide .

Prevention and early detection of OSCC and its pre-invasive intra-epithelial stages is still largely based on visual examination of the mouth, although a variety of molecular techniques have been tested and are likely to represent the ultimate goal of oral cancer research . A 9-year randomized controlled trial has shown that screening via visual examination of the oral mucosa under white light is effective in reducing mortality in individuals exposed to risk factors. Simple visual examination, however, is well known to be limited by subjective interpretation and by the potential, albeit rare, occurrence of dysplasia and early OSCC within areas of normal-looking oral mucosa. As a consequence, adjunctive techniques have been suggested to increase our ability to differentiate between benign abnormalities and dysplastic/malignant changes as well as identify areas of dysplasia/early OSCC that are not visible to naked eye. Chemiluminescence and autofluorescence are two relatively new techniques that have been investigated with variable results. Available studies have shown promising results, but strong clear evidence to support their effectiveness is still lacking. Major limitations include analysis of small sample sizes, lack of methodologically sound clinical trials, insufficient use of histologic and molecular mapping of optically altered mucosa, need of more detailed analysis of factors rather than cancer that can affect the optical qualities of the oral mucosa (e.g. inflammation, previous chemo- or radio-therapy), and also direct comparison with other detection methods. Toluidine Blue has been used by clinicians for many years, yet a clear demonstration of TB indications, limitations, as well as strong evidence from methodologically sound clinical trials is still lacking. Brush biopsy is another example of promising novel diagnostic technique that unfortunately has not been supported by robust evidence. Clinical trials have been performed but in the majority of cases results should be read with caution due to biases, variations in research objectives and methodological inconsistencies. At present, the utilization of these techniques in clinical practice is largely anedoctal and is principally directed to help experienced clinicians at improving their ability to detect dysplasia and early OSCC in high-risk individuals attending secondary and tertiary centers. Moreover, experienced surgeons use some of the described optic aids to improve the identification of a lesion's margins and extensions in the operatory setting, although it is not know then impact these techniques have on a patient's survival and risk of disease recurrence.

At present, molecular and genetic analysis is not a routine procedure for oral lesions in which biopsy is performed in daily practice. New methods under investigation that involve examination of molecular markers in exfoliated cells and in oral fluids and new imaging methodologies may contribute to future advances in diagnosis evaluation of response to treatment interventions and determination of prognosis of oral mucosal lesions. The future is promising for further development and evolution of oral-cancer diagnostic aids to enhance the quality of patient care provided by all clinicians.

References:  
  1. Rosenberg D, Cretin S. Use of meta-analysis to evaluate tolonium chloride in oral cancer screening. Oral Surg Oral Med Oral Pathol 1989;67 (5) :621-627.
  2. Driemel O, Kunkel M, Hullmann M, et al. Diagnosis of oral squamous cell carcinoma and its precursor lesions (in English and German). J Dtsch Dermatol Ges 2007;5 (12):1095-1100
  3. Hadorn DC, Baker D, Hodges JS, Hicks N. Rating the quality of evidence for clinical practice guidelines. J Clin Epidemiol 1996;49 (7):749-754.
  4. Lohr KN, Carey TS. Assessing “best evidence”: issues in grading the quality of studies for systematic reviews. Jt Comm J Qual Improv 1999;25 (9):470-479.
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  6. Myers EN. The toluidine blue test in lesions of the oral cavity. CA Cancer J Clin 1970;20 (3):134-139.
  7. Vahidy NA, Zaidi SH, Jafarey NA. Toluidine blue test for detection of carcinoma of the oral cavity: an evaluation. J Surg Oncol 1972;4(5): 434-438.
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  9. Mashberg A. Tolonium (toluidine blue) rinse: a screening method for recognition of squamous carcinoma—continuing study of oral cancer IV. JAMA 1981;245(23):2408-2410.
  10. Mashberg A. Final evaluation of tolonium chloride rinse for screening of high-risk patients with asymptomatic squamous carcinoma. JADA 1983;106(3):319-323.
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Authors : Dr. Pankaj Agarwal, Dr. Ashu agarwal, ,Dr. Ramballabh, ,Dr. Juhi,

Abstract
Due to the rarity of primary bone tumors, few physicians accumulate enough experience in the diagnosis and treatment of these neoplasias. Clinical management is best achieved through a multidisciplinary approach in which surgeon, radiologist, medical oncologist, and pathologist combine their expertise to establish both an accurate diagnosis and a rational treatment plan. The diagnostic algorithm of a primary tumor of the bone is, and always has been, a collaborative effort in which clinical, radiologic, and pathologic features have to be considered. In the majority of cases, the pathologist can rely exclusively on histopathologic examination to provide an accurate diagnosis. In some cases, however, a variety of ancillary studies have to be employed to distinguish entities that share morphologic characteristics. Currently, immunohistochemistry has limited application in the differential diagnosis of primary bone tumors, but occasionally, characterization of the antigenic profile is the only way to properly classify a given neoplasia. Furthermore, immunohistochemical analysis is helping us to establish the histogenetic origin of many entities and to understand their pathogenesis.

Introduction
The role of the pathologist in the management of bone tumors is essential. Accurate diagnosis of a given neoplasm determines not only the general patient’s prognosis but, more importantly, the type of therapeutic modality needed to achieve optimal results. Furthermore, new treatment protocols are constantly being developed, and it is the responsibility of the pathologist to properly classify a given tumor for successful inclusion in the appropriate protocol. When evaluating a bone tumor, however, the pathologist is confronted with several difficulties. Bone tumors are rare entities, and not all pathologists are exposed to bone pathology with the frequency needed to gain the necessary level of diagnostic confidence. Also, certain osseous tumors share histopathologic features and, in many cases, important diagnostic features may not be readily evident in small specimens. Finally, intramedullary lesions often must be decalcified, a process that may be associated with loss in cellular morphologic detail. All of these factors complicate the diagnostic process. Diagnosis for many entities can be reached by histopathology alone or can be interpreted in the context of clinicoradiologic findings, but for others, only a differential diagnosis can be reached without ancillary studies. Immunohistochemistry, however, is essential in identifying certain entities such as metastatic carcinomas and melanomas that can occasionally be confused, morphologically, with primary bone tumors. It is also routinely used to assign a phenotype to hematopoietic malignancies and to define histogenesis in morphologically related neoplasms such as the "small blue-cell" group of tumors. Several studies have shown that gentle decalcification methods preserve antigenicity relatively well for the most commonly used markers. Unfortunately, little is known about the antigenic specificity of normal bone tissue and bone neoplasias, and although several candidate antigens have been explored, reagents to detect bone-specific antigens are not yet available. The following is a review of the most commonly used markers and the antigenic profile of selected primary bone tumors and entities that are considered in the differential diagnosis.

Immunohistochemical Markers
Mesenchymal Marker Vimentin -- Although of limited value in differential diagnosis, vimentin is an abundant antigen that can be demonstrated in most properly fixed tissues and survives most decalcification procedures. It is used, therefore, to assess antigen loss during processing. Thus, if vimentin is not expressed in a tissue sample that should express it, interpretation should be either done with caution or entirely avoided. Epithelial Markers Cytokeratins -- Cytokeratins are expressed in carcinomas and in the vast majority, if not all, of epithelial-like sarcomas (epithelioid and synovial sarcomas). Certain tumors express profiles of cytokeratin subsets that have been reported to be more or less specific, although this is rarely helpful in routine diagnosis. Immunohistochemistry shows that the tumor cells are cytokeratin positive - carcinoma cells.

Epithelial Membrane Antigen -- Epithelial membrane antigen is expressed in approximately 75% of the epithelial-like sarcomas (epithelioid and synovial sarcomas) and in malignant peripheral nerve sheath tumors, leiomyosarcomas, histiocytes, and neoplasias of histiocytic origin, and in rare anaplastic lymphomas. Neuronal, Nerve Sheath, and Melanocytic Markers S-100 Protein (S-100) -- Widely distributed in peripheral and central nervous systems, the S-100 protein localizes to both the nucleus and the cytoplasm and, in the appropriate context, is one of the most useful markers. S-100 is expressed diffusely in neurofibromas and neurilemmomas, liposarcomas, ossifying fibromyxoid tumor, chondrosarcomas, and in 90% of clear-cell sarcomas, also known as melanomas of soft parts.3 Melanomas consistently express S-100, a feature that helps in the diagnosis of metastatic melanomas to the bone. Chordomas coexpress both S-100 and cytokeratin. Chondroblastoma. Immunoreactivity for S-100 protein in the neoplastic component.

Neurofilament Protein (NF) -- Useful in the differential diagnosis of small round-cell tumors, NF is expressed by many neuroblastomas, medulloblastomas, retinoblastomas, primitive peripheral neuroepitheliomas and, focally, in rhabdomyosarcoma and in malignant fibrous histiocytoma.4 Leu-7 (CD57) -- Although expressed in small round-cell tumors of childhood such as neuroblastoma, prominent expression in rhabdomyosarcoma limits its use in the differential of small round-cell tumors.5 Synaptophysin -- Synaptophysin is expressed by tumors of neuronal origin including neuroblastoma, ganglioneuroblastoma, olfactory neuroblastoma, melanotic neuroectodermal tumor of infancy, peripheral neuroepitheliomas, and rare rhabdomyosarcomas.6 Neuron-Specific Enolase -- Of limited use due to frequent, nonspecific, background staining, neuron-specific enolase is expressed in over half of neuroblastomas, one third of malignant melanomas, and a small percentage of nonneural tumors.7

Endothelial/Vascular Markers CD31 -- Detection of the antigen gpIIa, the cellular adhesion molecule PECAM-1 (platelet endothelial cell adhesion), has been shown to be expressed in 80% to 100% of angiosarcomas and hemangiomas. CD31 recognizes a 100kDA glycoprotein in endothelial cells

CD34 -- A sensitive marker for endothelial differentiation, CD34 is expressed by 70% of angiosarcomas, 90% of Kaposi’s sarcomas, and 100% of epithelioid hemangioendotheliomas. Factor VIII Antigen (FVIII) -- Restricted to endothelial cells and megakaryocytes, FVIII is less specific for endothelial neoplasms than are CD31 and CD34, although it is useful as a confirmatory marker (particularly in well-differentiated tumors).

Fibrohistiocytic Markers CD68 -- CD68 can be found in any tumor containing lysosomal granules or phagolysosomes. CD68 is expressed in only 50% of malignant fibrous histiocytoma cases and, given its nonspecificity, it should not be used as evidence of histiocytic lineage as initially reported. Miscellaneous Markers MIC-2 Gene Product (CD99) -- Located in the short arm of the sex chromosome, the MIC-2 gene product encodes a surface protein first described in T-cell and null-cell acute lymphoblastic leukemia. A recent antibody (HBA-71) detects an epitope present in Ewing’s sarcoma and peripheral neuroepitheliomas, alveolar rhabdomyosarcomas, ependymomas, and islet cell tumors. Alkaline Phosphatase, Osteonectin, Osteocalcin, and Collagens -- These proteins have all been used as potential bone tissue markers. Although in certain conditions the expression of these markers may be helpful, their specificity remains in question and reagents are not readily available to most laboratories.

Tumors

Bone-Forming Tumors Due to their central function in the process of mineralization, a group of proteins are considered to have some potential for tumor diagnosis: alkaline phosphatase, osteonectin, and osteocalcin. Osteocalcin is produced exclusively by bone-forming cells and therefore is receiving special attention as a specific marker. In the detection of bone-forming tumors, osteocalcin has been associated with 70% sensitivity and 100% specificity, compared with the 90% sensitivity and 54% specificity reported for osteonectin.13 At the present time, however, no specific marker is available to distinguish the bone matrix from its collagenous mimics.

Osteoma, Osteoid Osteoma, Osteoblastoma --
The diagnosis of these entities resides exclusively in morphologic features, and although a variety of lesions should be considered in the differential diagnosis, immunohistochemistry offers little help in the distinction. The nocturnal pain in osteoid osteoma, however, is mediated by prostaglandins, and it has been shown that in approximately 25% of osteoid osteomas, nerve fibers that express NF and S-100 are present in the reactive zone around the nidus and/or in the nidus itself. These fibers have not been observed in any other tumor, which suggests that the nerve supply of osteoid osteoma might serve as a marker in diagnostically difficult cases. Although occasionally observed in hematoxylin-eosin sections, NF and S-100 decorate the fibers and facilitate their detection. Osteosarcoma -- The differential diagnosis of osteosarcoma from other sarcomas (eg, malignant fibrous histiocytoma, fibrosarcoma, Ewing’s sarcoma) is important because of the specific therapy available for osteosarcoma patients. Most osteosarcomas express vimentin and, according to some authors, some tumors focally express cytokeratin and desmin, although these findings have not been widely confirmed.15-17 Bone matrix proteins, such as osteocalcin, alkaline phosphatase, and osteonectin, are expressed in osteosarcomas.13 However, their presence has also been detected in chondrosarcomas, Ewing’s sarcoma, fibrosarcomas, and malignant fibrous histiocytomas. Caution should also be used in the interpretation of focal expression of a variety of markers (eg, S-100, actin, epithelial membrane antigen) found occasionally in otherwise typical osteosarcomas. Extraskeletal osteosarcomas of the fibroblastic subtype often have sparse amounts of osteoid and can be differentiated from malignant fibrous histiocytoma on the basis of strong expression of alkaline phosphatase. Chondroblastic osteosarcoma and chondrosarcoma, however, cannot be distinguished immunohistochemically. Furthermore, it remains to be seen if the expression of CD31 or CD34 helps in the differential diagnosis between telangiectatic osteosarcoma and angiosarcoma. The different types of collagen present in the bone matrix are also produced by other tumors and therefore have no application in differential diagnosis. However, recent reports18 suggest that the basic calponin gene, a smooth muscle differentiation-specific gene that encodes an actin-binding protein involved in the regulation of smooth muscle contractility, is expressed in osteosarcomas and that this expression may have favorable prognostic implications.

Cartilage-Forming Tumors
Little is known about matrix biochemistry and cell differentiation in chondrogenic neoplasms. Normal chondrocytes typically express vimentin, S-100, and type II collagen. Neoplastic chondrocytes usually retain vimentin and S-100 expression, but little else is known about the expression of other antigens, and it is assumed that malignant cartilage-producing tumors have no specific antigenic profile.19 Although neoplastic chondrocytes in vitro can undergo full differentiation,19 the zonal expression of type X collagen is seen only in benign osteochondromas. In enchondromas, the pattern of expression is more randomly distributed within the tumor; in chondrosarcomas, with spindle-shaped cells and noncartilaginous extracellular matrix, only focal expression is seen.19 Proliferative markers like c-erb B2 are not observed in either normal cartilage or chondromas but are frequently seen in chondrosarcomas, suggesting that they may be useful in predicting biological behavior.

Osteochondroma, Periosteal Chondroma, Chondromyxoid Fibroma, Enchondroma --
Immunohistochemistry has little or no value in the differential diagnosis of this group of tumors. Chondromyxoid fibroma is a rare benign bone tumor of uncertain histogenesis that expresses S-100, a finding consistent with the cartilaginous nature of the lesion and supporting its possible relation to chondroblastoma. Chondroblastoma -- Chondroblastomas are unusual benign cartilage tumors of bone with well-defined histologic features. Chondroblasts express S-100, vimentin, and neuron-specific enolase and may show focal expression of osteonectin, cytokeratins, and epithelial membrane antigen. In approximately one third of the tumors, cytoplasmic expression of muscle-specific actin can be found in chondroblasts and chondrocytes. Moreover, these cells contain bundles of microfilaments with focal densities that are typical of myofilaments. Despite histogenetic considerations, immunohistochemistry helps in the distinction of chondroblastoma from other lesions that contain giant cells, such as giant-cell tumor and giant-cell reparative granuloma. These two entities do not express S-100, and their mononuclear population usually expresses histiocytic markers (eg, a1-chymotrypsin, lysozyme) not expressed in chondroblastoma. Chondrosarcoma -- Besides expression of S-100 and vimentin, chondrosarcomas may express Leu-7 and neuron-specific enolase. Although immunohistochemistry does not help in the distinction of chondrosarcoma from other cartilage-forming tumors, it is helpful in the distinction of chondrosarcoma from chordoma, which expresses epithelial membrane antigen, cytokeratins, and occasionally CEA.19

Fibrous and Fibrohistiocytic Tumors Fibrous Cortical Defect, Non-Ossifying Fibroma, Benign Fibrous Histiocytoma, and Desmoplastic Fibroma -- Immunohistochemistry has little or no application in the differential diagnosis of these entities.


Malignant Fibrous Histiocytoma (MFH) --
The list of entities included in the differential diagnosis of MFH is extensive. Immunohistochemistry helps in the distinction of MFH (CD68+) from leiomyosarcoma (CD68–); MFH (S-100–) from malignant neurilemmoma (S-100+); and MFH (osteocalcin–, alkaline phosphatase–) from fibroblastic osteosarcoma (occasionally positive for both). The distinction of cytokeratin-positive MFH from sarcomatoid carcinoma may be impossible by immunohistochemistry and is best accomplished by electron microscopy.

Smooth Muscle Tumors Leiomyosarcoma -- Primary leiomyosarcoma of the bone is a rare tumor in an unusual location. The diagnosis requires 1 exclusion of leiomyosarcoma in other non-osseous locations and 2 intramedullary location of the epicenter of the tumor (more than 70% of the mass) with only limited extraosseous extension. Osseous leiomyosarcomas frequently have the classic morphology, although epithelioid, myxoid, and pleomorphic variants can complicate the diagnosis. Expression of smooth muscle markers (smooth muscle actin, common muscle actin, and desmin) is consistently observed in the vast majority of tumors.

Vascular Tumors Angiosarcoma --
Primary angiosarcoma of bone is a rare, high-grade sarcoma of vascular origin. The clinicopathologic, immunohistochemical, and ultrastructural features of angiosarcomas are not well defined. Angiosarcomas strongly express vimentin and, at least focally, factor VIII-related antigen. CD34 antigen is detected in 74% of cases and cytokeratins in 35% of cases. Epithelial membrane antigen, S-100 protein, and HMB45 generally are not expressed. Fifty-five percent of the tumors have intracytoplasmic aggregates of laminin. Alpha-smooth muscle actin is demonstrated in a pericytic pattern in 24% of the tumors. Tumors have poor prognosis if more than 10% of the cells express MIB-1, a proliferation marker.

Lesions Containing Giant Cells In general, the osteoclasts and neoplastic giant cells of giant-cell tumor of bone and giant-cell reparative granuloma lack expression of HLA-DR (CD45), while giant cells of histiocytic origin and osteoclasts express CD68 and HLA-DR.

Giant-Cell Tumor (GCT) --
Although giant-cell tumor (GCT) of bone is a well-recognized neoplasm with distinctive clinical and histopathologic features, the histogenesis of the tumor cells, particularly of the mononuclear population, is still debated. GCT of bone is one of a few neoplasms in which macrophage/osteoclast precursor cells and osteoclast-like giant cells infiltrate the tumor mass. The gene transcripts of MCP-1, a monocyte chemo-attractant protein 1, are detected in all GCT and the protein is found in the cytoplasm of the stromal-like tumor cells of GCT of bone. This suggests that recruitment of CD68+ macrophage-like cells may be due to the production MCP-1 by stromal-like tumor cells. These CD68+ cells may originate from peripheral blood and could have the capability of further differentiating into osteoclasts within the tumor. However, the mononuclear stromal cells have been shown to express muscle actin (HHF35) and alpha-smooth muscle actin, while the osteoclast-like giant cells strongly coexpress muscle actin and CD68 but lack alpha-smooth muscle actin. These findings suggest a myofibroblastic origin. Therefore, the true histogenesis of the cell population, as well as the implications of these findings for GCT diagnosis in giant-cell tumors, remains unclear.

Giant-Cell Reparative Granuloma --
Giant-cell reparative granuloma (GCRG) is a reactive bone lesion that most often involves the jaws and, occasionally, the distal extremities. In extragnathic locations, GCRG may simulate other osteolytic giant cells lesions such as GCT of bone and aneurysmal bone cyst. Immunohistochemically, all cases showed expression of vimentin and actin in the stromal spindle-cell population and expression of CD68, vimentin, and leucocyte common antigen in the osteoclast-like giant-cell population. Since MIB-1 is expressed in approximately 6% of the stromal mononuclear population but in none of the giant cells, it has been suggested that the proliferative component is the stroma.

Conclusion
Although immunohistochemistry does not currently play the important diagnostic role in primary bone tumors that it plays in soft-tissue counterparts, research efforts to characterize the histogenesis of many of these neoplasias may offer new alternatives for diagnosis in the near future. For the distinction of primary tumors vs metastases of non-osseous origin and for the characterization of a small subset of neoplasias, such as those with small round-cell morphology, immunohistochemistry remains the technique of choice.

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