Clinical features and CT/MRI findings of pancreatic acinar cell carcinoma.
Evaluation of the imaging features of pathology-proven acinar cell carcinomas (ACCs) of the pancreas using computed tomography (CT). We reviewed the CT features, clinical presentations, and clinical outcomes of 15 patients (9 men, 6 women, mean age 62.3) with pathology-proven pancreatic ACCs. An abdominal radiologist retrospectively evaluated each patient’s initial imaging study with respect to the lesion’s size, location, attenuation (Hounsfield units) on arterial and venous phase images, peripancreatic lymphadenopathy, and distant metastases. Additional parameters studied included biliary and pancreatic ductal dilatation, intratumoral hemorrhage, calcification, the presence of cystic/necrotic components, and whether the tumor was intraparenchymal or exophytic. The ACCs in this series were evenly distributed between the head/uncinate and the tail, were predominantly exophytic (73%), tended to be large (average size 5.1 cm), and were mostly hypodense to the surrounding pancreas on both the arterial and venous phase images. A sizeable proportion demonstrated a cystic or necrotic component (53%) and/or an enhancing capsule (53%). Of those lesions in the head or uncinate process, very few resulted in pancreatic (28%) or biliary (14%) ductal dilatation. None of the lesions in this series showed internal calcification or intratumoral hemorrhage. While a prospective diagnosis is difficult, ACCs have several features which can differentiate them from ductal adenocarcinoma, including their large size, lack of biliary or pancreatic ductal dilatation, exophytic nature, and the presence of an enhancing capsule.