"Pure" primary large cell neuroendocrine carcinoma of the urinary bladder.

INTRODUCTION Large cell neuroendocrine carcinoma (LCNC) is defined in the urinary bladder, as in other sites, as a high-grade neoplasm exhibiting neuroendocrine features at the H&E level, high mitotic activity and evidence of neuroendocrine differentiation by immunohistochemistry. We report a case of pure bladder LCNC with review of the literature. METHODS A 68-year-old male presented with gross haematuria of two weeks' duration in October 2011. Transurethral resection and subsequently radical cystoprostatectomy (CP) with bilateral lymphadenectomy (L) were performed in December 2012. RESULTS Urinary cytology identified malignant cells. Histologically, the tumour showed organoid nesting, trabecular growth, rosettes and perilobular palisading patterns, suggesting neuroendocrine differentiation. Immunohistochemical staining showed intense positivity for CD56. DISCUSSION We examined all published pure bladder LCNC (12 cases) excluding mixed neoplasms. Small cell carcinoma of the urinary bladder pure LCNC of the bladder is a very aggressive malignancy, unresponsive to therapy, presents in an advanced stage and has a propensity for early metastasis. Prior to the advent of immunohistochemistry, such cases would most likely have been categorised as poorly differentiated, high-grade urothelial carcinomas.