Rhabdomyosarcoma of the urinary bladder with intraepithelial spread in an adult.

Rhabdomyosarcoma of the urinary bladder in adults is exceedingly rare. Reported cases have been of the embryonal botryoid type, as seen in children. We will describe a case of pleomorphic rhabdomyosarcoma occurring in the urinary bladder of an adult. In this case, we noted striking intraepidermal migration of tumor cells, resembling the epidermotropic growth characteristic of tumor cells in Paget disease of the breast. The pathological features of this apparently unique case form the subject of this report.