Well differentiated neuroendocrine tumor of the kidney: Report of a rare case with review of literature.

Neuroendocrine tumors (NETs) are uncommon tumors that exhibit a wide range of neuroendocrine differentiation and biological behavior. Primary NETs of the kidney, including carcinoid tumor, small cell carcinoma (SCC), and large cell neuroendocrine carcinoma (LCNEC) are exceedingly rare. Renal carcinoids are typically slow-growing tumors and pursue a variable clinical course. In contrast, SCC and LCNEC often present with locally advanced or metastatic disease and carry a poor prognosis. We herein report a rare cases of well-differentiated NET (carcinoid) in a 39-year-old male along with the immunohistochemical features. The rarity of these tumors poses a diagnostic and therapeutic challenge.