[Small cell neuroendocrine carcinoma of the urinary bladder: a case report]

A 60-year-old male was referred to our hospital with a complaint of asymptomatic gross hematuria. Cystoscopic examination revealed a non-papillary broad-based tumor on the posterior wall of the urinary bladder. Computed tomography revealed no evidence of metastases. Transurethral resection of bladder tumor (TUR-BT) was performed and muscle invasion was detected by histological examination of the specimen. Total cystectomy and ileal conduit formation were performed at the preoperative diagnosis of T2-3N0M0. Hematoxylin-eosin staining of the specimen revealed small cancer cells with hyperchromatic nucleus and scanty cytoplasm growing in the muscle layer of the urinary bladder and in the left obturator lymph nodes. Immunohistochemistry for neurospecific enolase showed diffuse staining in the cytoplasm of cancer cells, and ultrastructural study showed dense core granules. From these findings, the patient was diagnosed with small cell neuroendocrine carcinoma of the urinary bladder at the stage of pT3bpN1M0. Three courses of adjuvant chemotherapies with cis-platinum (CDDP) and etoposide were administered. The patient is still alive with no evidence of any recurrence at 22 months after the operation. This case suggests that treatment with combined total cystectomy and adjuvant CDDP and etoposide chemotherapies is effective against neuroendocrine carcinoma of the urinary bladder with regional lymph node metastases.