T. Saini, MS, Diplomats ABOMR;*

H.A. El-Abdin, BDS, FDSRCS;** N.O. Nartey, BDS, MSc***

The calcifying epithelial odontogenic cyst is an uncommon benign lesion. The cyst may sometimes be associated with benign odontogenic tumors. The lesion mostly effects patients under the age of 40 and occurs both in the mandible and maxilla. Involvement of the maxillary antrum seems to be a rare occurrence.

The calcifying epithelial odontogenic cyst is a rare lesion of the jaws. Gorlin et al,1 first described the condition and pointed out its close resemblance to the calcifying epithelioma of Malherbe. Gold2 rec­ ommends the more descriptive term of calcifying and keratinizing odontogenic cyst. The condition has been referred to as keratinizing ameloblas­ toma3 or melanotic ameloblastic odontoma.4 One of the histological features of the condition is the presence of ghost cells. Fejeskov and Krough5 are of the opinion that the lesion initially presents as a solid tumor, consisting mainly of ghost cells, and that the cyst development is a secondary pheno­ menon. They suggested a new descriptive term of ghost cell odontogenic tumor for the lesion.
A case is presented here in which the cyst occur­ red in the maxilla and encroached upon the maxil­ lary antrum. Only two cases have been reported in the literature to the knowledge of the authors, one by Gorlin1 and the other by Suddermath6 in which the cysts involved the maxillary antrum.
Case Report
A 34-year old Saudi male patient presented to the Oral Surgery Department complaining of a swelling and dull pain in the left maxillary region. The symptoms were of two years duration and the patient reported fluctuation and discharge from the sulcus.
The patient gave a history of extraction of his upper first left molar a year earlier. This was followed six months later by the removal of the upper left second molar, possibly on the assumption by the general practitioner that the lesion was a chronic dento-alveolar abscess and that drainage might resolve the swelling. Antibiotic was pre­ scribed then but the swelling persisted until his visit to the Oral Surgery Department in the school.
Clinical examination revealed noticeable facial asymmetry caused by a fluctuant swelling of the left maxilla extending from the first premolar to the tuberosity, resulting in obliteration of the left buccal sulcus. The mucosal covering of the swelling was of normal appearance. The area palatal to the upper last molar showed a hard swelling which was ten­ der. Aspiration was attempted and a serosanguine-ous fluid was removed.
Examination of radiographs revealed a well corti­ cated radio-translucent lesion of 2 cm. in diameter, encroaching upon the left maxillary antrum [Figs. 1 & 2]. Interiorly, the lesion extended from the left maxillary canine to the left third molar area. The postero- lateral wall of the antrum was expanded [Figs. 2 & 3]. The cortical outline appeared smooth and hydraulic. The medial wall of the antrum was intact [Fig. 3]. The frontal tomograms revealed massive obliteration of the left sinus except for a small area in the superior medial region. The lesion was separated from the residual antrum by a thin cortical plate. From the clinical and radiographic examination, the diagnosis of an odontogenic cyst was made.
Histologically, the lesion appeared cystic. The lining showed stratified squamous epithelium with variable thickness of 3 to 5 cells. Ghost cells and areas of calcification were also evident [Figs. 4a,b]. The connective tissue showed chronic inflammat­ ory cells infiltration, foci of granulation tissue and cholesterol clefts. The lesion was histologically diagnosed as a calcifying epithelial odontogenic cyst (C.E.O.C).
A mucoperiosteal flap was raised from the buccal aspect of the maxilla under general anaesthesia. The cyst wall was enucleated and found inseparable from the lining of the maxillary antrum.

The C.E.O.C. is known to involve mandible and maxilla with equal frequency.7 The age of occurrence of the cyst has been reported to very from 3 years to 80 years with definite peaking in the second decade. The cyst is usually asymptomatic unless secondarily infected.
Some cases were reported where the cyst concomitantly occurred with other odontogenic lesions. Praetorius8 described four types of conjunctional lesions with the cyst: namely, dentine producing ameloblastoma, odontoameloblastoma, ameloblastic fibro-odontoma and complex odontoma. The case presented in this report demonstrated sheets of ameloblast-like cells.
The presence of ghost cells characterizes the histological appearance of the lesion. Ultrastructur-ally, the ghost cells contain coarse fibrils which may due to incomplete keratinization of the cells.9 As the lesion matures, ghost cells undergo dysplastic calcification. Sometimes dentinoid or osteoid-like material is elaborated near the ghost cell-connective tissue junction.9 This may be due to an inductive effect of the epithelium. The calcifications, if present, will appear scattered radiopaque flakes in the radiograph. The other conditions which may simulate this radiographic appearance are the Pindborg tumor, ameloblastic fibro-odontoma, and adenomatoid odontogenic tumor.
Maxillary sinus involvement of the calcifying epithelial odontogenic cyst seems to be a rare occurrence. The patient in the case described by Gorlin was a 14-year-old female in whom the cyst encroached upon the right maxillary sinus, and was associated with a complex odontoma. Sudder-math described a cyst occurring in a 22-year-old male without any other associated lesions.
Enucleation of the cyst has provided total eradication of the lesion in all cases apart from the four published cases,5 in which the lesion recurred after surgical removal. In the present case, no sign of recurrence can be detected one year after the surgery.