Odontogenic Carcinosarcoma: Clinicopathologic Features of 2 Cases.

This study reports 2 odontogenic carcinosarcomas, including the clinicopathologic and immunoprofile characteristics of these rare tumors. The first case occurred in a 22-year-old male presenting a bilobular mass involving the gingiva and bone of the premolar region of the left mandible, with paresthesia of the lower lip. Microscopic examination revealed a tumor similar to ameloblastic fibrosarcoma, with atypical mesenchymal cells; however, the odontogenic epithelium also showed atypia. In the second case, a 16-year-old female had a painless, asymptomatic, large intraosseous mandibular lesion. The patient received radiotherapy to treat a rhabdomyosarcoma of the parotid 13 years before. The tumor was composed of atypical spindle cells, positive for vimentin and smooth muscle actin, intermingled with malignant odontogenic epithelium. Both epithelial and mesenchymal components of the tumors showed high index of p53- and Ki67-positive cells. The first case was diagnosed as odontogenic carcinosarcoma possibly originated from an ameloblastic fibrosarcoma, and the second as de novo odontogenic carcinosarcoma possibly caused by previous radiotherapy.