Abstract
Clear cell odontogenic carcinoma (CCOC) is a low-grade malignant neoplasm that affects the jaws. We report an 18 cm massive case of mandibular CCOC in a 43-year-old female. The tumor was composed of nests and cords of round to polygonal monomorphic clear cells separated by prominent stromal hyalinization. Immunohistochemically, the tumor cells showed focal cytokeratin 5/6 positivity and intracytoplasmic PAS-positive granules and were negative for S100 and after diastase treatment (PAS-D). Molecularly, this case was positive for EWSR1 rearrangement by FISH. The following should be included in the histopathological differential diagnosis: hyalinizing clear cell carcinoma of the salivary gland, clear cell variant of central mucoepidermoid carcinoma, clear cell variant of calcifying epithelial odontogenic tumor, and metastatic renal cell carcinoma. CCOC is a rare entity, with only 79 cases reported in the mandible. This case highlights the propensity for CCOC to exhibit invasiveness, destructive nature, and facial disfigurement if left untreated.
Highlights
Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumor with less 120 cases reported in the jaws since it was first described by Hansen et al in 1985 [1]
Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic neoplasm characterized by Ewing sarcoma region 1 (EWSR1) gene rearrangement
Most cases of CCOC reported in the literature were described before EWSR1 rearrangement was identified in the tumor
Summary
Clear cell odontogenic carcinoma (CCOC) is a rare malignant odontogenic tumor with less 120 cases reported in the jaws since it was first described by Hansen et al in 1985 [1]. CCOC presents as an infiltrative tumor composed of nests, sheets, or cords of monomorphic round to polygonal clear epithelial cells separated by variable hyalinized stroma [4]. They are positive for cytokeratins, p63, and PAS, are diastase-sensitive (demonstrating intracytoplasmic glycogen), and are negative for mucicarmine and myoepithelial markers such as S100, SMA, and calponin [4, 5]. We report a massive case of CCOC of the mandible in a Nigerian patient, performing limited immunohistochemical stains (CK5/6 and S100), special stains (PAS and, PAS-D), and FISH molecular analysis for EWSR1 rearrangement
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