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Clear cell change in a calcifying odontogenic cyst K. H. Ng, B.D.S., M.Sc., F.D.S.R.C.P.S.,* and C. H. Siar, B.D.S., M.Sc., F.D.S.R.C.P.S.,** Kuala Lumpur, Malaysia A case of calcifying odontogenic cyst exhibiting clear cell change is described. Histomorphologic similarities to the clear cell type of calcifying epithelial odontogenic tumor were noted and the importance of differential diagnosis from clear cell types of salivary gland neoplasms and metastatic hypernephroma are emphasized. (ORAL. SURG. ORAL MED. ORAL PATHOL. 60~417-419, 1985) T he calcifying odontogenic cyst (COC) was first characterized by Gorlin and his associates’ in 1962 and is now recognized as a distinct entity by the World Health Organization.* Since its inception more than 150 caseshave been reported and several reviews have been documented. The COC is generally regarded as a benign lesion of odontogenic origin, which can present as a cyst or as a neoplasm.3 Praetorius and co-authors) classified the COC into two main subentities: a unicystic type and a neoplastic type. They proposed that the latter should be called dentinogenic ghost cell tumor. It is well-recognized that the COC often occurs in association with other lesions such as odontomas.4 A pigmented variant has also been reported.5 Clear cell change in a COC has not been previously docu- mented in the literature. The purpose of this article is to describe a case that exhibited this unusual change. CASE REPORT A 29-year-old Malay woman was first seen with a chief complaint of a swelling involving the right side of the mandible. This extended from the mandibular first premo- lar to the mandibular second molar. The preliminary clinical diagnosis was radicular cyst. Enucleation of the cyst and curettage were performed, and the cyst lining was sent for microscopic examination. *Head, Division of Stomatology, Institute for Medical Research. Jalan Pahang. **Lecturer, Department of Oral Pathology and Oral Medicine, Faculty of Dentistry, University of Malaya. Macroscopic findings The surgical specimen consisted of a piece of cyst lining measuring approximately 3.5 X 2.4 X 0.8 cm. Microscopic findings The specimen was fixed in formalin and processed in the routine manner. Paraffin sections were prepared and initially stained with hematoxylin and eosin. Subsequent sections were stained with alcian blue, Southgate mucicar- mine, and PAS-diastase. Microscopically, the specimen consisted of a fibrous connective tissue wall lined with stratified squamous epi- thelium. The epithelium had a well-defined basal cell layer composedof columnar cells that exhibited polarization of their nuclei away from the basement membrane. Superfi- cial to this was a loosely structured network of stellate reticulum-like cells and focal masses of ghost cells undergoing varying degrees of calcification (Fig. 1). The histologic appearance conformed to that necessary for a diagnosis of calcifying odontogenic cyst as defined by the World Health Organization Committee for the Histo- logical Typing of Odontogenic Tumors, Jaw Cysts and Allied Lesions.* An unusual finding was the presence of nests, cords, and islands of large polyhedral cells in the subepithelial zone of the connective tissue wall (Fig. 2). These cells had clear or finely granular cytoplasm with small ovoid nuclei often displaced to the periphery. Stains for mucin and glycogen were negative. These clumps of cells were sometimes closely related to areas of hyaline material or dentinoid which were present in a subepithelial location (Fig. 3). DISCUSSION A review of the English-language literature revealed that clear cell change in the COC has not 417
