Primary pleomorphic sarcoma of the ovary with rhabdomyosarcomatous differentiation.

A 49-year-old patient presented with a right ovarian mass, which, on microscopy, showed to consist of haphazardly oriented large pleomorphic cells with abundant cytoplasm. Periodic acid Schiff stain was positive but negative with diastase digestion. Immunohistochemical staining with Desmin showed intense cytoplasmic positivity in almost all the cells. Cytokeratin, epithelial membrane antigen, smooth muscle actin, HMB-45, S-100 and neurone-specific enolase were negative. Immunohistochemical staining with Myogenin showed intense nuclear positivity. There was no other primary tumor on extensive search. A diagnosis of primary sarcoma of the ovary with rhabdomyosarcomatous differentiation was made. The incidence of similar tumors of the ovary are low and therefore little data are available on this uniformly lethal tumor. Thus, such cases need to be reported to pool experience so that the tumor can be diagnosed early.