RHABDOMYOSARCOMA WITH RHABDOID-LIKE FEATURES

We describe an unusual case of a rhabdomyosarcoma (RMS) in that it had rhabdoid-like cells histologically and occurred in a female who had u ndergone bone marrow transplantation for chronic myelogenous leukemia. The tumor was composed of loosely cohesive cells with abundant eosino philic cytoplasm and exhibited PAS-negative paranuclear inclusions. Th e tumor cells had positive vimentin, muscle-specific actin, sarcomeric actin and desmin immunoreactivity. Ultrastructurally, the tumor cells contained aggregates of thin and thick filaments. In situ hybridizati on did not detect human papillomavirus or cytomegalovirus DNA, or EBV DNA or RNA. The tumor fulfilled the current criteria for a diagnosis o f RMS; however, it could not be further classified. The tumor appears to have a good prognosis as there has been no evidence of recurrence f ive years after resection. As this is the first case report, to our kn owledge, of this type of tumor following bone marrow transplant, the s ignificance of this association is not yet clear.