Calcifying cystic odontogenic tumor associated with a complex odontoma

ABSTRACT

@#We present a case of a 16-year-old lad with a one year history of gingival mass of the left maxillary alveolar ridge. Excision revealed a cystic mass with brown fluid and irregular calcified material within the cavity. Histopathologic examination of the cyst lining shows a stratified cuboidal epithelium with palisading of the basal layer. The cells of the latter show reverse nuclear polarization reminiscent of ameloblastic epithelium. The superficial layers have a stellate reticulum-like appearance and contain large eosinophilic polygonal ghost cells. (Figure 1, 2) Some of the ghost cells show calcifications. (Figure 3) Sections from the hard, bony fragments show haphazard deposition of dentin and enamel-like material. (Figure 4) With these features, this case was called a calcifying cystic odontogenic tumour in association with a complex odontoma. Calcifying cystic odontogenic tumor (CCOT) is a benign neoplasm characterized by an ameloblastoma-like epithelium with ghost cells that often show calcification.1 It comprises only 2% of all benign odontogenic neoplasms.2 There is equal distribution of involvement for the maxilla and mandible, no sex predilection, with most cases diagnosed at the 2nd to 3rd decade of life.1,2 The classic histologic findings are the presence of a stratified epithelium consisting of cuboidal to columnar cells with reverse polarization of the basal layer and the presence of ghost cells. A stellate reticulum-like appearance of epithelial cells is also seen. Ghost cells are the most characteristic feature of CCOT and this may represent an abnormal type of keratinization or the coagulative necrosis of the odontogenic epithelium.