Endocrine cells in ampullary carcinoma.

BACKGROUND/PURPOSE: As ampullary carcinoma originates from four anatomical regions, it may have different behaviors depending on its origin. We documented the presence of endocrine cells found in ampullary carcinoma, and we studied the clinicopathological implications of their presence.

METHODS: We immunohistochemically examined the presence of an endocrine component in 62 surgically resected specimens of ampullary carcinoma, and we studied the clinicopathological differences between endocrine component-positive cases and endocrine component-negative cases.

RESULTS: Endocrine cells were detected in 16 cases (26%); 11 cases had many endocrine cells, and five cases had scattered endocrine cells. Serotonin-positive cells were detected in all 16 cases, in which six cases had many positive cells. Several somatostatin-positive cells were detected in three cases. Endocrine cells were detected in ampulloduodenal polypoid lesions (two cases) and ampullopancreaticobiliary ducts (14 cases). The histology of 15 of the 16 endocrine component-positive ampullary carcinomas was the intestinal type. Pancreatic invasion and lymph node involvement were observed less frequently in endocrine component-positive cases (P < 0.01). There were no significant differences with respect to immunoreactivity for carbohydrate antigen (CA) 19.9, carcinembryonic antigen (CEA), and p53 overexpression, and K-ras mutations.

CONCLUSIONS: Endocrine component-positive ampullary carcinoma seemed to be derived from the ampullopancreaticobiliary common duct or the ampulloduodenum, and to behave less aggressively than endocrine component-negative carcinoma.