Abstract
An epidermoid cyst (EC) is a benign soft tissue lesion that can form in any part of the body. However, the occurrence of EC in the maxilla is extremely rare. Herein, we report a rare case of an intraosseous EC located in the posterior region of the maxilla. A 13-year-old woman was referred to our department for evaluation of an intraosseous radiolucent lesion in the right maxilla. The asymptomatic lesion appeared well-defined and unilocular (15 × 20 mm) on the panoramic radiograph and computed tomography scan, and was surgically extracted under general anesthesia. Based on the results of the histopathological examination, a final diagnosis of EC was confirmed. EC should be included in the differential diagnosis of radiolucent lesions of the jaws and maxilla.
1
Introduction
An epidermoid cyst (EC) is a benign soft tissue lesion that can occur on any part of the body. In general, males are affected more frequently than females [ ]. The majority of the cases develop in the testicles and ovaries (80%) and only 7% have been reported to occur in the head and neck region. Furthermore, only 1.6% of the cases develop within the oral cavity thereby accounting for 0.01% of all oral cavity cysts [ ]; the floor of the mouth is the most favored site. The development of an intraosseous EC is extremely rare. Moreover, the number of reported cases of EC in the maxilla is fewer than that in the mandible. Herein, we describe a rare case of an intraosseous EC located in the posterior region of the maxilla.
2
Case report
A 13-year-old woman was referred to our department for evaluation of an intraosseous radiolucent lesion located at between the roots of first and second molar tooth in the right maxillary region. On examination, the alveolus represented normal clinical findings without any expansion or swelling; there was no pain or tenderness. There were no visible changes on the surface of the mucosa around the lesion. Her past dental and medical histories were not contributory, and there was no history of trauma or surgery to the right maxilla.
A panoramic radiograph and computed tomography revealed the presence of a well-defined unilocular radiolucent lesion (15 × 20 mm) with a sclerotic margin in the posterior part of the right maxilla. The first and second molars were displaced due to the cystic lesion. A thickening of the mucous membrane of the maxillary sinus was observed due to communication between the sinus and the cystic lesion ( Fig. 1 ).
Based on the clinical and radiographic examinations, odontogenic keratocyst (OKC), unicystic ameloblastoma, or aneurysmal bone cyst was considered as a differential diagnosis. Surgical extraction of the cystic lesion was performed under general anesthesia. The first and second molars were preserved due to the age of the patient. The cyst was not exposed to the bone surface; a whitish cystic wall along with cheese-like material was observed due to the rupture of the cystic wall ( Fig. 2 ). Owing to the perforation of maxillary sinus, the mucous membrane of sinus adjacent to the lesion was removed as much as possible.
Histopathological examination revealed that the cystic cavity was lined by stratified squamous orthokeratinized epithelium with a well-developed granular cell layer resembling the epidermis. There was no evidence of any dermal appendages ( Fig. 3 ).
Based on these results, a final diagnosis of EC was confirmed. No recurrence of the cyst or development of maxillary sinusitis was observed during the six-month postoperative follow-up. A computed tomography scan revealed that no findings of recurrence for EC, and the improvement of thickening of the mucous membrane of the maxillary sinus ( Fig. 4 ).
