Extraskeletal myxoid chondrosarcoma of the left buccal mucosa.

Extraskeletal chondrosarcoma (ECS) is a rare malignant neoplasm of bone or soft-tissue origin, characterized by the presence of spindle cells admixed with well-differentiated cartilage or chondroid stroma. A case of ECS is reported in a 102-year-old woman who presented with a painful swelling of 2 cm in the left buccal vestibular area. Orthopantomography was insignificant. Biopsy and histopathological examination revealed a tumor composed of an undifferentiated small round cell component that surrounded a myxoid matrix of malignant cartilage. Immunohistochemical studies showed the tumor cells to be positive for nuclear S-100 protein immunostaining, focally positive for vimentin and synaptophysin, and negative for epithelial membrane antigen, desmin, chromogranin, Leu-7, glial fibrillary acid protein, actin muscle-specific, cytokeratin, carcinoembryonic antigen, and CD99 (MIC2). The proliferative index (MIB-1) was 20%. The tumor was treated by surgery with wide margins. There was no evidence of disease at one-year follow-up. This report presents a very rare case of ECS of the left buccal mucosa of the maxilla, and describes the histological characteristics and the immunoprofile.