[Carcinosarcoma and papillary transitional cell carcinoma coexisting in the same bladder]

A case of synchronically coexistent carcinosarcoma and transitional cell carcinoma, with separate neoplastic processes in the same urinary bladder is presented. This tumour association is as far as we know, the second case reported in the literature. Carcinosarcoma was formed by an epithelial component represented by a high level transitional cell carcinoma and a mesenchymal component characterized by an unspecific fusocellular sarcoma with chondrosarcomatous differentiation. An immunohistochemical analysis was performed, confirming the dual nature of the carcinosarcoma.