Immunocytochemical study of an endometrial diffuse clear cell stromal sarcoma and other endometrial stromal sarcomas.

Intermediate filament composition was studied in the following endometrial stromal tumors: low-grade stromal sarcoma (endolymphatic stromal myosis), high-grade stromal sarcoma with an associated adenocarcinoma (collision tumor), diffuse clear cell stromal sarcoma and a mesodermal mixed tumor (carcinosarcoma). The tumor cells of the stromal tumors as well as the mesenchymal elements of the mixed mesodermal tumor were decorated exclusively with antibodies to vimentin. Desmin was not demonstrated in these tumor cells. A biochemical study of the cytoskeletal filaments present in the low-grade stromal sarcoma revealed, in addition to vimentin, beta and gamma actin as seen in normal endometrial stroma. Cytokeratins were only identified in epithelial components which were present in some of these tumors. Intermediate filament typing in these endometrial neoplasms contributes to the elucidation of histogenetic problems, may delineate mesenchymal from epithelial elements, may separate muscle from stromal lesions and in one instance helped to define a hitherto unreported diffuse clear cell stromal sarcoma.