Rhabdomyosarcoma with pseudolipoblasts arising in ovarian carcinosarcoma: a distinctive postchemotherapy morphologic variant mimicking pleomorphic liposarcoma.

[pleomorphic liposarcoma]

We describe a case of ovarian carcinosarcoma occurring in a 60 -year -old female . The neoplasm was excised after neoadjuvant chemotherapy and contained a predominant heterologous pleomorphic rhabdomyosarcomatous component in which there were numerous multivacuolated rhabdomyoblasts that strongly mimicked lipoblasts . The clear cell variant of rhabdomyosarcoma is rarely documented , but this case shows a highly unusual finding in which the rhabdomyoblasts show the prominent multivacuolation with nuclear indentation characteristic of and indistinguishable from pleomorphic lipoblasts . This appears to represent a posttreatment phenomenon . As this finding might conceivably occur in other rhabdomyosarcomas after chemotherapy , we highlight the potential for diagnostic confusion with pleomorphic liposarcoma , which is usually diagnosed by morphology so that immunohistochemistry for muscle markers might not be performed .