Unusual presentations of pancreatic ductal adenocarcinoma on computed tomography and magnetic resonance

The characteristics of pancreatic ductal adenocarcinoma (PDAC) on multidetector computed tomography (MDCT) and magnetic resonance (MRI) are well known, and typically consist of a hypovascular focal lesion with poorly defined margins. This lesion may be accompanied by secondary signs such as abrupt cutoff of the pancreatic and/or bile duct with upstream dilation of both, dilation of the biliary and pancreatic ducts, atrophy of the parenchyma proximal to the tumor, and extension into the retroperitoneum and regional vascular structures. However, it is essential for the radiologist to be familiar with unusual presentations of PDAC that may mimic other pathologies and potentially go unnoticed if interpreted as benign or of different origin, posing a diagnostic challenge. The aim of this review is to recognize uncommon imaging features that may be seen in the context of PDAC and their main differential diagnoses.