OBJECTIVETo study the clinical and pathologic characteristics of small cell neuroendocrine carcinoma of urinary tract.

METHODSAll cases of urinary tract carcinoma encountered in the General Hospital of People Liberation Army during the period from 1999 to 2010 were retrospectively reviewed. The clinicopathologic data of small cell neuroendocrine carcinomas were further analyzed, with literature review.

RESULTSA total of 16 cases of small cell neuroendocrine carcinoma were identified, including 10 from urinary bladder, 2 from ureter, 3 from renal pelvis, and 1 multifocal tumor involving renal pelvis and ureter. There were altogether 8 males and 8 females. The median age of the patients was 63 years (range = 24 to 79 years). Gross hematuria (11 cases) represented the main presenting symptom. Four patients had flank pain and 4 had urinary irritation symptoms. Seven patients underwent radical cystectomy. Six other patients underwent radical nephroureterectomy, 1 partial cystectomy, 1 TURBT and the remaining case biopsy only. The size of the tumor ranged from 0.8 to 8.0 cm (median = 4.5 cm). Histologically, 15 cases represented mixed small cell neuroendocrine carcinoma (with 13 mixed with transitional cell carcinoma and 2 with adenocarcinoma). Immunohistochemical study showed positive staining for neuroendocrine markers. On presentation, 1 patient was in stage pT1, 7 in stage pT2, 6 in stage pT3, 2 in stage pT4. Six patients died of the disease after operation. The overall survival was 25 months and the 5-year survival rate was 32.4%.

CONCLUSIONSSmall cell neuroendocrine carcinoma of urinary bladder is a highly malignant disease and associated with poor prognosis. The diagnosis relies on detailed histologic examination. Early diagnosis, when coupled with cystectomy or nephroureterectomy and adjuvant chemotherapy, represents the mainstay of management.