Large dentigerous cyst associated with an impacted canine- A case report

Author : Nasir A Salati.

Abstract

Presentation of dentigerous cyst with large swelling is rare and in a young patient in early twenties has to differentiated from unicystic ameloblastoma and adenomatoid odontogenic tumor. Here, we are presenting a case report of a twenty year old female with large extra-oral swelling in maxillary left region associated with mild epiphora and dizziness. It was decided to surgically bridge the graft using bone harvested from left iliac crest after proper pathologic and anesthetic evaluation.

Introduction

Dentigerous cyst is one of the most prevalent types of odontogenic cyst and is associated with crown of an unerupted or developing tooth. Dentigerous cyst accounts for more than 24% of jaw cysts and it is the most common developmental odontogenic cyst of oral region found in second and third decade, occasionally associated with subjective symptoms1. A very substantial majority involve mandibular third molar followed by maxillary permanent canine, mandibular premolars and maxillary third molars2, 3. Males are more commonly affected than females. Here we are presenting a rare case of dentigerous cyst of maxillary antrum in a female patient associated with impacted canine tooth attached to its supero-lateral wall, causing bulging and thinning of its anterior wall and causing mild pain and uneasiness.

Case Report

A 22 year old young female patient presented with progressive swelling of left cheek since 3 months. [FIG 1] There was history of mild pain and occasional epiphora associated with the swelling. There was no intraoral complaint. There was no previous history of trauma. On examination the swelling was rounded in shape, firm in consistency but egg shell crackling was present on deep palpation. No intraoral lesion was detected. No bruit or pulsation was observed. There were no signs of acute or chronic infection. On intra-oral examination, there were retained maxillary left deciduous canine, impacted right and left maxillary third molars. The overall oral hygiene of the patient was good and there was no history of any sensitivity. A provisional diagnosis of dentigerous cyst was made. Unicystic ameloblastoma was considered as second most probable diagnosis. Considering the age and gender of the patient, adenomatoid odontogenic tumor and ameloblastic fibroma were also considered in differential diagnosis.

Investigations and Surgical approach

OPG revealed impacted impacted right and left maxillary third molars, missing lower right third molar, impacted lower left third molar and maxillary left impacted canine. Fine needle aspiration cytology revealed the cystic character of the swelling. CT scan of the face revealed presence of a radio-opaque opacity in the cyst swelling arising from the supero-lateral wall, which was suggestive of cystic swelling of the left maxillary antrum with expansion and thinning of anterior maxillary wall. It was decided to surgically bridge the graft using bone harvested from left iliac crest. After proper anesthetic evaluation, it was decided to excise the cystic swelling through extra oral approach. During surgical procedure, it was found that cystic swelling was encroaching the maxillary antrum area and associated with impacted canine. There was obvious thinning of anterior wall of the maxilla [FIG 2]. The specimen was submitted for histo-pathological examination. Macroscopic examination revealed the cyst lining attached around cemento-enamel junction of a maxillary permanent canine teeth measuring about 4x4 cm [FIG 3]. The microscopic examination revealed epithelial lining consisting of flattened cells resembling reduced enamel epithelium. The fibrous capsule was found to be collagenised with diffuse inflammatory cells with focal areas of mucous cells at certain places. [FIG 4]. The OPG was done postoperatively which

revealed large radiolucent area in maxillary left canine region [FIG 5].

Discussion

Dentigerous cyst can be defined as one which encloses the crown of an unerupted tooth and is attached at the cemento-enamel junction.4 It is a cyst arising by separation of follicle from around the anatomical crown of an unerupted tooth within the jaws.5 It sometimes is associated with premolars, particularly second premolars.6 About 1.44 per cent of impacted teeth may undergo dentigerous cyst transformation.8 The dentigerous cyst develops around an unerupted tooth by accumulation of fluid between the reduced enamel epithelium and the enamel. It has been suggested that the pressure exerted by a potentially erupting tooth on an impacted follicle obstructs the venous outflow and there by induces rapid transudation of serum capillary walls. The increased hydrostatic pressure of this pooling fluid separates the follicle from the crown with or without reduced enamel epithelium. Unlike other odontogenic cysts, the epithelial cells that line the lumen of dentigerous cyst arise from reduced enamel epithelium origin and possess an unusual ability to undergo metaplastic transition into other epithelial cell types. Because of this unusual ability, the epithelial lining often contains focal areas of orthokeratinization or a mixture of mucin-secreting and ciliated cells. Large dentigerous cysts can cause facial asymmetry particularly when involving maxillary antrum, body or ramus of the mandible.10, 11.Radiographically, these cysts show unilocular radiolucent areas associated with crowns of unerupted teeth, have well defined sclerotic margins with trabeculations are seen which resembles multilocularity. Three radiological variations are observed. In central variety, the crown is erupted symmetrically and pressure is applied to the crown of tooth which may push it away from its direction of eruption. In lateral type, the radiographic appearance is due to dilatation of the follicle on one aspect of the crown. This type is seen when an impacted mandibular third molar is partially erupted so that its superior border is exposed. In circumferential type, the entire tooth appears to be enveloped by cyst. Sometimes, the dilated follicle resembles dentigerous cyst .if the width is less than 4mm.7 On rare occasions, some untreated dentigerous cysts have potential to develop odontogenic tumors like ameloblastoma and malignancies like oral squamous cell carcinoma and mucoepidermoid carcinoma.9, 12.

Other complications

I. Infection is the most complication of a cyst in the jaw. Microbes gain access to the cyst through odontogenic passages (i.e. carious cavities, periodontal pockets etc.) or through minor external injuries. Infection causes the sclerotic border of the lesion to get blurred in radiograph. Normal asymptomatic lesions are rendered painful by infection, which prompts the patient to seek treatment.
II. Effects on associated teeth : Surgical enucleation of large dentigerous cysts is associated with teeth can cause disruption of blood supply leading to pulp death and discoloration in some cases.
III. Pathologic fracture : A pathologic fracture occurs if a large defect is not adequately managed by filling or grafting, after surgical enucleation.

The various treatment approaches are based on patient age, cyst site and size, involvement of vital structures by the cyst, and the potential for normal eruption into occlusion of the impacted tooth involved. Usually dentigerous cysts are treated by enucleation, decompression or complete excision with marsupilization done in some cases. Occasionally, extraoral approach is used particularly if external plate fixation or if defect is to be replaced by other bone grafts.13

References

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