Primary signet ring cell carcinoma of the urinary bladder successfully treated with intra-arterial chemotherapy alone.

A 65-year-old man presented with the complaint of gross hematuria. Cystoscopy revealed a sessile tumor on the left bladder wall. It was diagnosed as primary signet ring cell carcinoma of the bladder (T3bN0M0). The patient did not want surgical treatment. Therefore, three courses of arterial infusion of carboplatin were administered at 3-week intervals. Complete remission was obtained and has been maintained for 44 months. Our case appears to be the first report of successful treatment with chemotherapy alone of an infiltrating signet ring cell carcinoma of the bladder.