Carcinosarcoma of the urinary bladder - An aggressive tumor with diverse histogenesis - A clinicopathologic study of 4 cases and review of the literature

Objective.-Carcinosarcomas of urinary bladder are rare malignant neoplasms. Seventy-eight cases have been previously described. The histologic composi tion of these tumors is variable, but diagnosis requires the presence of bo th epithelial and mesenchymal malignant components. We report 4 additional cases, with an emphasis on unusual histologic features. Methods.-Histologic and immunohistochemical examinations were performed on bladder tumors from 4 patients. Clinicopathologic features of previously re ported and current cases were reviewed and summarized. Results.-Four patients (3 men, 1 woman) age 54 to 77 years were found to ha ve polypoid masses in the urinary bladder. In all cases, histologic examina tion showed biphasic neoplasms with distinct mesenchymal and epithelial com ponents. The morphologic and immunohistochemical characteristics of the tum ors varied. One of the cases was remarkable for the presence of liposarcoma , malignant peripheral nerve sheath tumor, and micropapillary urothelial ca rcinoma. Two Of the patients died 2 years after diagnosis, which is consist ent with the previously reported aggressive nature of urinary bladder carci nosarcomas. Conclusions.-Carcinosarcomas of the urinary bladder are rare, aggressive ma lignant neoplasms. To our knowledge, a liposarcomatous component has been r eported in only 1 case previously, and components of micropapillary urothel ial carcinoma and malignant peripheral nerve sheath tumor have not been rep orted previously in carcinosarcomas of the urinary bladder. Because of the aggressive biologic behavior of these tumors, they should be identified pro mptly and treated appropriately.