Clear cell odontogenic carcinoma and clear cell ameloblastoma: A single clinicopathologic entity? A new case and comparative analysis of the literature

Background: Clear cell odontogenic carcinoma (CCOC) is histologically characterized by solid sheets and nests of clear cells. Clear cell ameloblastoma (CCAM) is histologically characterized by an ameloblastomatous component intermixed with an extensive clear cell component. In all literature reviews, no separation has been made between the clinicopathologic features of CCOC and CCAM. Purpose: We sought to review and analyze the clinicopathologic and radiologic features and the biologic behavior of CCOC and to compare them with those of CCAM to evaluate the possible separation between the 2 lesions. Materials and Methods: A MEDLINE search of the English-language literature was carried out for CCOC and CCAM. Cases were classified according to their histologic features. Results: A total of 27 cases of CCOC (26 from the literature and 1 new case) and 8 cases of CCAM were found. CCOC patients showed a male-to-female ratio of 1:2.4, with a mean age of 59 years. CCAM patients showed a male-to-female ratio of 1.7:1, with a mean age of 44 years. CCOC and CCAM were predominantly found in the mandible. Both CCOC and CCAM showed a high rate of recurrence (50% and 63%, respectively) and metastases (33% and 25%, respectively). Several patients with CCOC presented with metastases at time of diagnosis, whereas patients with CCAM usually developed metastases only after several recurrences. Conclusion: Based on the relatively small number of cases in the literature on CCOC and CCAM, it is difficult to confidently separate the 2 lesions. Both lesions should be considered low-grade malignancies and could well represent a clinicopathologic continuum of a single disease entity rather than 2 separate lesions.