Role of immunohistochemistry in diagnosis of a rare bladder tumor

Neuroendocrine tumors (NETs) are commonly located in the respiratory and gastrointestinal tract; however, these tumors can rarely be found in the urinary bladder. NETs comprise <1% of all bladder tumors; usually intermixed with urothelial carcinoma and its variants. We report a case of primary neuroendocrine carcinoma of urinary bladder in an adult female with a history of smoking and hematuria. The present case highlights the importance of immunohistochemistry in arriving at an accurate diagnosis and thereby differentiating this tumor from other clinical mimics.