Malignant carcinoid tumor of the transverse colon

This code signifies a malignant neuroendocrine tumor originating in the transverse segment of the large intestine. These tumors arise from enterochromaffin cells and can produce various hormones, leading to carcinoid syndrome in some cases. Histologically, they are characterized by uniform cells with granular cytoplasm.

Apply this code when documentation explicitly states a malignant carcinoid tumor located in the transverse colon. This diagnosis is typically confirmed by biopsy and histopathological examination. Use for primary tumors, not metastatic sites.

• Ensure the documentation specifies "malignant" and "transverse colon."
• Do not use for benign carcinoid tumors; refer to the D3A category.
• Code any associated carcinoid syndrome separately, if present and documented.