[Sarcomatoid carcinoma of the urinary bladder with a spontaneous perforation: a case report].

A 65-year-old woman was referred to our clinic with gross hematuria. Cystoscopy revealed a non-papillary and non-pedunculated tumor on the left lateral wall of the bladder. A piece of necrotic tissue obtained from the bladder irrigation was histologically squamous cell carcinoma. A perforation at the left lateral wall of the bladder was found on the cystogram. Bone scintigraphy showed multiple metastases and computed tomography scans showed multiple lymph node metastases in the pelvic cavity. The clinical diagnosis was bladder carcinoma of T4N2M1 stage with an abscess due to a spontaneous perforation. Total cystectomy with bilateral ureterocutaneostomy was performed. She died due to sepsis 13 days after the operation. Histologically, the tumor was composed of carcinomatous and sarcomatous elements. The carcinomatous element was compatible with squamous cell carcinoma and the sarcomatous element was composed of undifferentiated malignant spindle cells. Immunohistochemical examination showed that the carcinomatous component was positive for keratin and human chorionic gonadotropin (HCG) and the spindle cell component positive for vimentin, desmin and HCG. Therefore, we diagnosed the tumor as sarcomatoid carcinoma. We reviewed 56 cases of carcinosarcoma of the bladder in Japan and discussed the clinicopathology of the disease.