Background: Although ampullary carcinoid tumors (ACs) are often categorized clinically as duodenal carcinoid tumors (DCs), there are distinct clinical and pathologic differences.
Methods: Clinical, histopathologic, and immunohistochemical features of 12 ACs were compared with those of 53 DCs that did not involve the ampulla.
Results: Patients with AC were ages 28-74 years (mean, 54.9 years); 8 were males and 4 were females. Five were white and three were black; the race of four patients was not known. The size of ACs ranged from 0.2 to 5.0 cm in greatest dimension. There were no significant differences between AC patients and DC patients with respect to male predominance, race, tumor size, and mitotic rate. The insular growth pattern was more common in AC; the cribriform type was more common in DC. Four of 12 ACs contained psammoma bodies, versus none of 53 DCs (P = 0.001). The rate of metastasis was similar in patients with AC (4 of 12, 33%) compared with DC patients (14 of 53, 26%). In DC patients, involvement of the muscularis propria, a size greater than 2 cm, and mitotic activity were significantly correlated with metastatic risk. In AC patients, tumor size and mitotic activity had no correlation with metastatic potential. One AC had features of an atypical carcinoid tumor; there were none in the duodenal group. One-half of patients with AC presented with jaundice versus 7% of patients with DC (P = 0.005). Three patients (25%) with AC had von Recklinghausen disease versus 0 of 53 patients with DC (P = 0.003). Immunohistochemically, tumor cells expressed somatostatin in 67%, serotonin and cholecystokinin in 17%, insulin in 25%, and glucagon and gastrin in 0% of ACs. In contrast, 56% of DCs expressed gastrin (P < 0.001).
Conclusions: Carcinoid tumors of the ampulla differ clinically, histologically, and immunohistochemically from carcinoid tumors elsewhere in the duodenum.