Invasive carcinomas derived from intraductal papillary mucinous neoplasms of the pancreas: a long-term follow-up assessment with CT imaging.

Objective: To describe computed tomography (CT) findings of invasive carcinoma derived from intraductal papillary mucinous neoplasms (IPMNs) of the pancreas during long-term follow-up.

Methods: Follow-up CT findings of 5 patients with IPMNs progressing to invasive carcinomas were respectively reviewed for 12 to 63 months. All patients underwent thin-section 3-phase helical and/or multislice CT.

Results: Invasive carcinomas were detected as hypo- (n = 3) or hyperattenuating (n = 2) solid masses in the pancreatic parenchyma on contrast-enhanced CT. Hypoattenuating masses were mostly visualized on arterial dominant phase images. In 4 branch-duct type IPMNs, the solid masses appeared with (n = 3) or without (n = 1) dilatation of the main pancreatic duct after 3 to 5 years. In the remaining combined-type IPMN, a solid mass was detected on initial CT and progressively increased during the follow-up.

Conclusions: Arterial dominant phase CT is useful for detecting invasive carcinoma derived from IPMNs and is an effective follow-up method.