Malignant carcinoid tumor of the kidney

This code identifies a rare, slow-growing neuroendocrine tumor originating in the kidney. These tumors arise from enterochromaffin-like cells and are characterized by their potential to secrete vasoactive substances, though this is less common with renal primaries. Histologically, they often present with uniform cells arranged in nests, cords, or trabeculae.

Assign this code for documented cases of primary malignant carcinoid tumor definitively diagnosed as originating in the kidney. This diagnosis is typically confirmed through biopsy and immunohistochemical staining. Use when the pathology report explicitly states "malignant carcinoid tumor of the kidney."

• Differentiate from metastatic carcinoid tumors to the kidney; this code is for primary renal involvement.
• Ensure the documentation specifies "malignant" as benign carcinoid tumors are coded differently.
• Review pathology reports carefully for the exact site and malignancy status to avoid miscoding.