Malignant neoplasm of ampulla of Vater

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

Assign this code for confirmed diagnoses of adenocarcinoma or other primary malignant neoplasms specifically located within the ampulla of Vater. Documentation should clearly state the primary site of the malignancy as the ampulla, often supported by imaging, endoscopic findings, and pathology reports.

• Differentiate from malignancies of the head of the pancreas (C25.0) or common bile duct (C24.0), which are distinct anatomical sites.
• Ensure pathology confirms malignancy; do not use for benign polyps or inflammatory conditions of the ampulla.
• Sequence as the primary diagnosis when the ampullary neoplasm is the reason for the encounter or treatment.