Sarcomatoid carcinoma of the urinary bladder. Clinicopathologic analysis of 18 cases with immunohistochemical and electron microscopic findings.

Sarcomatoid carcinoma is a rare tumor in the urinary bladder and accounts for approximately 0.3% of all bladder malignancies. In this study, the clinicopathologic findings of 18 cases are described. Distribution of sex and age and clinical symptoms are not distinctive from transitional cell carcinoma. The tumor behaves as a high-grade malignancy with advanced initial stage and unfavorable outcome. Surgery is the therapy of choice. Histological differentiation from true sarcoma may be difficult. Recognition rests on the co-existence of an overt carcinomatous component or demonstration of the epithelial nature by immunohistochemistry or electron microscopy.