Urinary Cytologic Features of Primary Large Cell Neuroendocrine Carcinoma of the Urinary Bladder

BACKGROUND: Little is known about urine cytology of large cell neuroendocrine carcinoma (LCNEC) of the bladder. We report a case of primary LCNEC of the bladder, focusing on urinary cytology. CASE: A 76-year-old woman who had a history of transurethral resection for urothelial carcinoma of the bladder visited our hospital because of intermittent gross hematuria. Urinary cytology on this visit identified atypical cells, interpreted initially as urothelial carcinoma. Cystoscopy detected a tumor apart from the previous bladder urothelial carcinoma. The diagnosis of LCNEC was pathologically confirmed after the transurethral resection; subsequently radical cystectomy and bilateral pelvic lymphadenectomy were performed. Based on the review of urine cytology for this tumor, neoplastic cells possessed rosette and nuclear molding arrangements with finely or coarsely granular, hyperchromatic nuclei. The average nuclear size of the neoplastic cells was 10.3 microm, whereas the average cell size was 14.9 microm. These cells were immunocytochemically positive for synaptophysin, consistent with LCNEC. The operative course for this patient was uneventful, and LCNEC had not recurred in the 48 months since cystectomy. CONCLUSION: Our observations suggest that urinary cytology in combination with morphometry and immunocytochemistry may be a potentially useful method for the detection of LCNEC of the bladder.