Monophasic, glandular, synovial sarcomas and carcinomas of the soft tissues.

In soft tissues, malignant tumors with epithelial qualities are usually metastatic carcinomas. A rare, primary, soft-tissue tumor that is uniformly carcinoma-like is the monophasic, glandular, synovial sarcoma. We studied three cases of carcinoma-like neoplasms of soft tissue. In one primary tumor and two recurrent tumors of soft tissue, the histologic patterns were uniformly glandular. For the two recurrent tumors, the primary lesions were a classic, synovial sarcoma and a biphasic, synovial sarcoma with a histiocytic, stromal component. By inference, the third tumor, a primary "carcinoma" of soft tissue, may represent a de novo, monophasic, glandular, synovial sarcoma. Synovial sarcoma should be considered in the differential diagnosis of carcinoma like tumors discovered in the soft tissues.