A and B, Coronal (A) and axial (B) contrast-enhanced CT images show masslike enlargement of pancreatic head with central cystic focus (arrow, A), which is relatively isodense to surrounding pancreas, as well as diffuse pancreatic ductal dilatation. There is subtle soft tissue in pancreaticoduodenal groove (arrow, B), which is best seen on axial image. Endoscopic ultrasound suggested presence of discrete mass in this location (although biopsy results were negative), and patient underwent Whipple procedure under assumption that mass represented pancreatic adenocarcinoma. However, postsurgical pathology revealed it to be segmental form of groove pancreatitis with involvement of pancreatic head.
C, Histologic specimen (H and E, ×40) shows dilated pancreatic duct with thick proteinaceous secretions. Multiple smaller dilated ducts are present. Ducts are lined by low cuboidal-to-columnar mucinous ductal epithelium.