Malignant neoplasm of appendix

This code signifies a primary cancerous tumor originating in the appendix. It refers to the uncontrolled growth of abnormal cells within the appendiceal tissue, which can be various histological types such as adenocarcinoma, carcinoid, or mucinous adenocarcinoma.

Use this code when documentation clearly states a diagnosis of primary malignant neoplasm of the appendix. This typically occurs following pathological confirmation from a biopsy or surgical resection specimen. It is appropriate for both initial diagnosis and subsequent encounters related to the primary appendiceal malignancy.

• Always confirm the primary site of the malignancy; do not use for metastatic disease to the appendix.
• Specify the histological type of the neoplasm with an additional code if known and documented (e.g., C7A.090 for malignant carcinoid tumor of the appendix).
• Ensure documentation differentiates between benign appendiceal tumors (e.g., D12.6) and malignant neoplasms.