Abstract
Background : Although small cell carcinomas of neuroendocrine origin are commonly identified in the lung, they are known to occur in other organs but are relatively rare in the urinary tract. We report herein on two cases of small cell carcinoma arising primarily in the ureter with tumor cells observed in the urine on cytological examination.
Case : Case 1 was a woman in her eighth decade. A urologic consultation was obtained for complaint of right back pain, and atypical cells were observed in her urine sample obtained by urethral catheter. These atypical cells were dispersed or appeared as small aggregates partly with a molding arrangement. The cells showed bare nuclei with fine granular chromatin. Case 2 was a man in his ninth decade. He was admitted to the hospital for asymptomatic hematuria and small atypical cells were observed in his urine sample. These cells showed a high nuclear-cytoplasmic ratio, irregular shaped nuclei with dense chromatin and prominent nucleoli. Histologically, small sized tumor cells with sparse cytoplasm and dense nuclei were closely arranged.
Conclusion : Small cell carcinomas are known, albeit uncommonly, to arise from the urinary tract. One factor might be the difficulty in finding characteristic neoplastic cells. To verify whether the neoplastic cells have the phenotype of neuroendocrine origin, an additional technique such as immunocytochemistry will be needed for adequate diagnosis in the future.
