Malignant neoplasm of ampulla of vater

This code signifies a primary cancerous tumor originating in the ampulla of Vater, a small opening where the bile duct and pancreatic duct join before emptying into the small intestine. This malignancy can obstruct bile flow and pancreatic secretions, leading to jaundice and pancreatitis.

Apply this code when documentation clearly indicates a primary malignant neoplasm confirmed to be located specifically within the ampulla of Vater. This diagnosis is typically established through imaging studies (e.g., CT, MRI, ERCP) and confirmed by biopsy.

• Differentiate from malignancies of the head of the pancreas or distal common bile duct, which have distinct ICD-9-CM codes.
• Ensure the pathology report explicitly states "ampulla of Vater" as the primary site of the malignancy.
• Do not use for secondary or metastatic tumors to this site; instead, code the primary malignancy and the secondary site.