Sarcomatoid Carcinoma of the Urinary Bladder: Case Report and Review

Sarcomatoid variant of urothelial carcinoma of the urinary bladder is a rare malignant neoplasm, accounting for less than 1% of all bladder carcinomas. Sarcomatoid carcinomas are aggressive malignancies, which by definition are biphasic neoplasms with both an epithelial and a mesenchymal component. 1 Sarcomatoid carcinoma is the preferred terminology according to the World Health Organization classification for any biphasic tumor of urothelial origin, with or without heterologous elements, and now encompasses what has been previously referred to as carcinosarcoma, although this terminology is still occasionally used by some authors. 2 In this article, a case report of a typical bladder sarcomatoid carcinoma is presented along with differential diagnoses, morphology, and molecular aspects of pathogenesis.