Primary small cell carcinoma of the bladder: a report of 25 cases.

Primary small cell carcinoma of the bladder is a rare condition with approximately 100 cases reported to date. An incidence of 0.7% small cell carcinoma was found in a total series of bladder tumors diagnosed in Western Sweden during a 2-year period. We describe 22 patients with primary small cell carcinoma followed to death or for at least 6 years. Three additional cases were diagnosed at autopsy. Of 18 patients with stages T2M0 to T4M0 cancer treated with locoregional therapy 5 (28%) had no evidence of disease after a median observation of 10 years (range 6 to 18) and 13 died of disease after 0.5 to 19 months (median 7.3). Two patients with metastatic disease were treated with systemic chemotherapy but died within 15 months. Two patients died shortly after the diagnostic biopsy. Our study and a review of the literature indicate that primary small cell carcinoma of the bladder is less aggressive than its pulmonary counterpart and that some patients can be cured by transurethral resection, or partial or radical cystectomy combined with radiotherapy.