A novel case of concurrent renal tumors: chromophobe renal cell carcinoma and carcinoid tumor of the kidney with brief review of renal neuroendocrine tumors.

Renal cell carcinoma of chromophobe type is a malignant neoplasm with characteristic large cells that exhibit prominent cell membranes. Primary renal carcinoid tumors are rare tumors with the histological appearance similar to well-differentiated neuroendocrine tumors at other sites. Chromophobe renal cell carcinoma with neuroendocrine differentiation is exceedingly rare. The authors describe a case of a chromophobe renal cell carcinoma and carcinoid tumor of the kidney presenting as distinct masses in the same kidney in a 34-year-old male. The histologic and immunohistochemical features of both the tumors were characteristic with no overlapping features. The carcinoid tumor presented at a higher stage with nodal metastasis. To the best of the authors' knowledge, this is the first case of 2 morphologically distinct tumors, one chromophobe renal cell carcinoma and the other primary carcinoid tumor in the same kidney.