Clinical features and CT/MRI findings of pancreatic acinar cell carcinoma.

To retrospectively review the clinical features and computed tomography (CT) and magnetic resonance imaging (MRI) findings of PAAC so as to improve the accuracy of imaging diagnosis. Seventeen patients with pathologically proven PAAC were enrolled. Their clinical and imaging findings were retrospectively reviewed. The median age of the patients was 56 years (range, 7-74 years). The tumors were located in any part of the pancreas or exophyitc growth, with a median maximal diameter of 68 mm. Thirteen masses presented with ovoid shape. Nine masses had less clear boundaries. Eleven masses showed a variable degree of intratumoral hypodense or necrosis before contrast administration on CT images. Five masses showed hypointense on unenhanced T1 weighted images and hyperintense on T2 weighted images. After contrast administration, the most common enhancement pattern was slight enhancement on arterial phase and persistent enhancement on portal vein phase. Infiltration of tumor into duct and vessels was not common. Five and 2 patients developed hepatic metastasis and local lymphadenopathy, respectively. By the end of the last follow-up, 11 patients survived free of disease. PAAC should be included in the differential diagnosis when a bulky, ovoid, heterogeneous mass, with clear or less clear margins, in the pancreas or peripancreas, with slight and persistent enhancement after contrast administration on CT or MRI images is seen, particularly in elder men.