Small cell carcinoma of the urinary bladder. A clinicopathologic analysis of 22 cases.

Small cell carcinoma of the urinary bladder is an uncommon tumor. The authors report the clinicopathologic findings in a series of 22 cases. Fifteen men and 7 women were studied; their ages ranged from 51 to 87 years (mean, 62.4 years). The most frequent presentation was hematuria (94.4%). At diagnosis, three patients had Stage B disease, six had Stage C, and ten had Stage D (unknown stage in three). Histologically, 6 were oat cell type tumors, 11 were of intermediate cell type, and 5 were of combined cell type. Immunohistochemical studies demonstrated positivity for neuron-specific enolase in ten of ten cases, cytokeratin in seven of ten cases, chromogranin in eight of nine cases, serotonin in seven of nine cases, and S-100 protein in four of ten cases. Neuroendocrine differentiation was seen in five of seven cases examined by electron microscopy. Treatment and follow-up data were available for 19 patients: 10 (52.6%) were dead of disease, 5 (26.3%) were alive and well, 3 (15.8%) were alive with disease, and 1 (5.3%) died of an unrelated cause. The 2-year survival rate was 50% for patients with Stage B, 25% for patients with Stage C, and 33% for patients with Stage D disease. Although overall survival was poor, some cases responded well to therapy. Based on the authors' experience, radical cystectomy with adjuvant chemotherapy appears to be the treatment of choice.