External Beam Radiation and Brachytherapy forProstate Cancer: Is It a Possible Trigger of Large Cell Neuroendocrine Carcinoma of the Urinary Bladder ?

Neuroendocrine tumors commonly involve the respiratory and gastrointestinal systems. Primary genitourinary neuroendocrinetumors are rare, accounting for less than 1% of all bladder carcinomas. Four histopathologic subtypes have been described. Amongthose, large cell neuroendocrine carcinoma (LCNEC) is the least common, is more aggressive, and generally presents in anadvanced stage with poor prognosis compared to transitional cell bladder carcinoma. There is no standardized treatment regimenbecause of the rarity of the disease. Herein, we present a case of 72-year-old male patient with previously treated prostate cancer,who received external beam radiation therapy and high dose brachytherapy, presenting with intermittent hematuria. Cystoscopyand transurethral resection of bladder tumor (TURBT) were performed. The histopathology and immunohistochemistry wereconsistent with large cell neuroendocrine carcinoma (LCNEC). Further studies are required to proof the higher risk ofneuroendocrine carcinoma of the bladder in patients treated with external beam radiation therapy and brachytherapy for prostate