Biphasic clear cell odontogenic carcinoma: An aggressive metastatic neoplasm

Abstract

AbstractIntroductionThe recent classification of odontogenic tumours includes the entities clear cell odontogenic carcinoma (CCOC) and clear cell ameloblastoma (CCAM) under the unifying name CCOC. The lack of ameloblastic differentiation in many cases of CCOC, its more aggressive behaviour and unique molecular profile suggest a distinct entity which merits its own standing in the classification of odontogenic carcinomas.Case reportA 53‐year‐old male presented with excessive hyperplastic tissue in the anterior maxilla. Microscopic examination disclosed a biphasic clear cell neoplasm with nests of polygonal clear cells, surrounded by intensely eosinophilic flattened cells. The tumour cells were immunoreactive for MNF 116, CK 14, CK 19, CK 5 and EMA. The proliferation index, Ki67, was low and its expression, similar to the basal‐cell‐specific cytokeratins (CK 14 and CK5), was confined to the peripheral cells. Molecular studies confirmed EWSR1 gene rearrangements. An anterior maxillectomy was performed, supplemented with radiotherapy. Three years after resection, multiple metastatic bodies were detected in the lung and the patient passed away 1 year later.ConclusionThis case further supports the notion that CCOC with biphasic histomorphology appears to have a high mortality rate, and it may be wise to treat and monitor these patients more aggressively.