Expression of intermediate filaments in soft‐tissue sarcomas

Abstract
Monospecific antibodies and indirect immunofluorescence microscopy were used to investigate the presence of cytoskeletal intermediate filaments of the keratin, vimentin and desmin types in 43 soft-tissue sarcomas. The results showed that vimentin was present in the neoplastic cells of all types of soft-tissue sarcomas studied, whereas keratin was absent, the only exception being the epithelial-like cells in biphasic synovial sarcoma. The presence of desmin was confined to leiomyosarcomas and rhabdomyosarcomas, which usually showed desmin-positivity. In addition, malignant fibrous histiocytomas occasionally displayed some desmin-positive cells. Thus, determination of intermediate filaments is of aid in the histogenetical diagnosis of tumors, because keratin-positivity largely excludes the possibility of a sarcoma, and desmin-positivity aids in recognizing leiomyosarcomas and rhabdomyosarcomas.