Sarcomatoid carcinoma of the urinary bladder: a case report and review of the literature

Abstract

Sarcomatoid variant of urothelial carcinoma of the urinary bladder is a rare malignant neoplasm, which is defined with biphasic neoplasm with both an epithelial and a mesenchymal component by histopathological and immunohistochemistry. It is responsible for 0.3% off all bladder carcinomas. The aim of this study was to present the histopathological and immunohistochemical findings of a case of sarcomatoid carcinoma of the urinary bladder and to review the relevant literature. A 75-year-old man was presented to our hospital with hematuria. 6.5x5.8 cm tumor was found in the urinary bladder at ultrasonography. Magnetic resonance imaging demonstrated a large irregular-shaped 9x5 cm tumor involving the right posterolateral wall of the urinary bladder and an atrophic kidney. The patient underwent cystoprostatectomy, left nephrectomy, and lymph node dissection. Macroscopically, a 7.5x6.1x1.8 cm ulcero-vegetating tumor mass infiltrating the bladder base, right-left side wall, anterior-posterior wall, and trigon was seen. Microscopically, this tumor was composed of high-grade urotelial carcinoma and mesenchymal differentiation areas with a wide eosinophilic cytoplasm, vesicular nucleus, distinct nucleolus and spindle-shaped areas. Immunohistochemically, mesenchymal differentiation areas were stained prominently with vimentin, keratin. The case was diagnosed as sarcomatoid carcinoma. Tumor metastasis was detected in the prostate and in bilateral pelvic lymph nodes. Although the clinical findings and the age of diagnosis of sarcomatoid urothelial carcinoma are similiar to conventional urothelial carcinoma, it has a worse prognosis. The presented case died 2.5 months after surgery. Sarcomatoid carcinoma seems to represent the final common pathway of urothelial carcinoma dedifferentiation. Keeping this aggressive tumor type in mind is essential for a correct treatment approach.