FIG. 1.

Site-specific classification of ampullary carcinoma. a IAPN-associated carcinomas are characterized by a prominent pre-invasive neoplasm (gray areas) that grows predominantly as an exophytic mass within the distal ends of the common bile duct and main pancreatic duct. b Ampullary duct carcinomas have minimal pre-invasive component, and invasive component (black areas) forms a plaque-like stricture at the distal ends of the ducts. c Ampullary duodenum carcinomas form ulcerovegetative tumors that grow predominantly on the duodenal surface of the ampulla. d Carcinomas that do not fit in any of these categories are classified as NOS. IAPN intra-ampullary papillary-tubular neoplasm, NOS not otherwise specified