Sarcomatoid carcinoma of urinary bladder:a clinicopathologic analysis

Objective To explore the clinical, histopathological features of sarcomatoid carcinoma of the urinary bladder with emphasis on its differential diagnosis. Methods Clinical data and image findings were reviewed, and histopathological and immunohistochemical changes were observed in a case of sarcomatoid carcinoma of the urinary bladder. Results The tumor, measuring 5cm×4cm×3cm, was located in the right wall of the bladder, cauliflower_like shape. Histologically, the tumor was characterzed by biphasic proliferation of malignant epithelial and stromal elements. The epithelial component showed spuamous elements. The stromal component was largely a hypercellular spindle cells element and partly showed rhabdomyoid differentiation. Immunohistochemical staining showed that the epithelial component was positive for CK, CK17 and the sarcomatous component was positive for vimentin,desmin,actin (α-sarcomeric), and both were negative for S_100, CK20. Conclusions Sarcomatoid carcinoma of the urinary bladder is a rare, highly aggressive and malignant neoplasm characterized by an intimate admixture of carcinoma and malignant soft tissue neoplasm. The morphologic and immunohistochemical characteristics of the tumors vary. The initial biopsy of this patient is critical to diagnosis.