Carcinosarcoma of the urinary bladder is a rare neoplasm that is histologically composed of malignant epithelial and mesenchymal components. The etiology of sarcomatoid tumors is unclear, but smoking and history of previous radiotherapy or chemotherapy may lead to bladder disorders and to the formation of sarcomatoid carcinoma. These neoplasms behave as highly aggressive tumors and optimal treatment is uncertain. Herein, we report a case of sarcomatoid carcinoma of urinary bladder presenting as a giant intravesical mass in a 61-year-old man complaining of macroscopic hematuria.KEY WORDS: Bladder carcinosarcoma; Urothelial carcinoma; Prognosis. had a catheter without any other remarkable finding. Laboratory test results were normal. Whole abdominal ultrasonography (USG) showed a 9 x 8 cm mass which filled the bladder. Abdominopelvic computerized tomography (CT) showed a 9 x 7 cm mass lesion, originating from the right lateral wall of the bladder and occupying the entire bladder (Figure 1). A written informed consent was obtained from the patient and cystoscopic examination was performed under general anesthesia. The mass, which originated from the bladder neck and filled the bladder, was incompletely resected. Pathological examination showed a biphasic pattern, and the result was reported as a sarcomatoid carcinoma. The epithelial component included an adenocarcinoma and squamous-cell carcinoma, whereas the sarcomatous component included a spindle-cell and chondrosarcoma. As the all resection specimen consisted of tumor tissues, we were unable to evaluate the depth of invasion. Computed tomography showed no sign of lymph node or organ metastasis. Four weeks after transurethral resection (TUR-BT), radical cystoprostatectomy, lymph node dissection, and ileal conduit surgery were performed. Cystoprostatectomy specimen had a 10 x 8.5 cm tumor in-diameter (Figure 2). After histological examination, tumor was reported as a high-grade sarcomatoid carcinoma, pT2a, pN0, pMx. The histological pattern consisted of 70% sarcomatous component (spindle-cell and chondrosarcoma), and 30% epithelial component (adenocarcinoma and squamous-cell carcinoma). All surgical margin samples and lymph nodes were reported as normal. Four days after the surgery, the patient died due to myocardial infarction.