Carcinosarcoma of the submandibular gland. An autopsy case.

We present a rare case of submandibular gland carcinosarcoma occurring in a 45-year-old male patient. His clinical history revealed that the carcinosarcoma had developed from a carcinoma ex mixed tumor in three years. In spite of repeated resection, intensive chemotherapy and irradiation, the tumor recurred and grew rapidly, and the patient died of hemothorax caused by rupture of a pulmonary metastatic tumor. The fourth recurrent tumor and autopsy specimens showed features of carcinosarcoma consisting of three tumor components, i.e., undifferentiated carcinoma, and chondrosarcomatous and osteosarcomatous growth. The metastatic nodules in both lungs and pulmonary hilar lymph nodes showed the same pattern. Immunohistochemically, the chondrosarcomatous cells were positive for vimentin and S-100 protein, and for epithelial markers such as epithelial membrane antigen (EMA) and cytokeratin (MA-902). Undifferentiated carcinoma cells, on the other hand, were partially positive for muscle actin other than cytokeratin (KL 1). Ultrastructurally, desmosome-like structures were seen in the chondrosarcomatous cells. These findings suggest that the sarcomatous lesions might have originated from epithelial cells.