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 M 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.