Carcinoid tumor of the ampulla of Vater

Carcinoid tumors arising from the ampulla of Vater are rare, and their magnetic resonance (MR) imaging findings have not been reported in the literature to date. We report a case of carcinoid tumor of the ampulla of Vater and discuss the characteristic MR imaging findings. The tumor was isointense relative to the muscle on both the T1- and T2-weighted images with heterogeneous enhancement after gadolinium administration. Both the common bile and the pancreatic ducts were dilated on the MR cholangiopancreatography.