Small cell carcinoma of the bladder. Two cases diagnosed by urinary cytology

BACKGROUND: Primary small cell carcinoma (SCC) of the bladder is a rare but important entity. We report two cases of SCC of the bladder diagnosed by urinary cytology. CASES: A 71-year-old male (case 1) and a 79-year-old female (case 2) presented with asymptomatic gross hematuria. Urinary cytology in case 1 showed the presence of a few undifferentiated malignant small cells and many transitional cell carcinoma (TCC) cells with a bloody and necrotic background. The former cells were small and round, with naked, hyperchromatic nuclei and finely granular chromatin. Pathologic diagnosis after total cystectomy was TCC > SCC > adenocarcinoma, T2M0N0. Urinary cytology of case 2 showed the presence of many undifferentiated malignant small cells and many TCC cells with or without squamous metaplasia. Cytologic features of the former cells were almost the same as those in case 1. Moreover, these cells were neuroendocrine marker positive by immunocytochemistry. Pathologic diagnosis after tumor resection was SCC and TCC > squamous cell carcinoma, T1b. CONCLUSION: The prognosis of primary SCC of the bladder is usually poor. Because our cases were found by urinary cytology at a relatively early stage, both have been well, without any evidence of recurrence, 30 and 25 months after surgery even without adjuvant therapy.