Carcinoid tumors of the pancreas: dynamic CT and MRI features with pathological correlation.

BACKGROUND: Carcinoid tumor of the pancreas is rare, and there are few reports that described its CT or magnetic resonance imaging (MRI) findings. We describe the characteristic CT and MRI findings in four cases of carcinoid tumor of the pancreas.
METHODS: Radiologic and pathologic features were analyzed in four patients. All patients underwent triple-phase dynamic CT and MRI.
RESULTS: The tumor size in the four cases ranged 15-20 mm and intratumoral calcification was detected in one case. On triple-phase dynamic CT, the peak enhancement of the tumors was seen at the arterial dominant phase in three cases; the remaining one was at the portal venous phase with prolonged contrast-enhancement effect. The tumors showed low to high signal intensity on T2-weighted images. Dilatation of the main pancreatic ducts (MPDs) distal to the tumors was seen in three cases, in which tumor invasion into the MPDs was pathologically confirmed. Furthermore, the tumors having mild to severe fibrosis pathologically invaded into the peripancreatic lymphatics or nerves.
CONCLUSION: It would be characteristic of carcinoid tumor of the pancreas to be well enhanced at the arterial dominant phase on dynamic CT, and to highly invade into the MPDs and the peripancreatic lymphatics or nerves.