Pure sarcomatoid carcinoma of maxillary sinus and nasal cavity simulating malignant fibrous histiocytoma.

Although a few cases of sinonasal carcinoma with focal sarcomatous differentiation have been reported, pure sarcomatoid carcinoma has not been reported in the English literature. Imaging studies and gross inspection in a 60-year-old man with left-sided face pain revealed a mass in the left maxillary sinus and nasal cavity. A large incisional biopsy specimen from the nasal cavity revealed proliferation of malignant spindle and round cells with a malignant fibrous histiocytoma (MFH) pattern. Tumor giant cells were scattered, and there were areas of a vague storiform pattern. Mitotic figures were numerous. Carcinomatous component was not recognized. The histologic diagnosis was storiform-pleomorphic MFH. Tumor cells were positive for pancytokeratins AE1/3, KL-1, and CAM5.2 and cytokeratin (CK) 18, vimentin, CD68, p53, Ki-67 (labeling, 90%), α₁-antitrypsin, and α₁-antichymotrypsin and negative for pancytokeratin WSS, CK 34βE14, CK7, CK8, CK14, CK19, CK20, epithelial membrane antigen, S-100 protein, desmin, α-smooth muscle actin, CD34, HMB45, chromogranin, synaptophysin, myoglobin, CD45, CD30, and CD15. Because keratins were positive in tumor cells, a diagnosis of sarcomatoid carcinoma simulating MFH was made. The patient was treated with chemoradiation without significant effect and died 9 months after initial examination.