Imaging findings of pancreatic ductal adenocarcinoma
A. Pancreatic enlargement is usually focal and best appreciated in the pancreatic body and tail. Diffuse enlargement is often secondary to pancreatitis caused by the neoplasm.
B. Enlargement and distortion of the pancreatic contour or shape are the most frequent findings of pancreatic cancer.
C. Difference in density or echogenicity are present.
US: US usually detects a hypoechoic mass, compared with a normal pancreas, with ill-defined borders.
CT: Pancreatic ductal adenocarcinoma usually appears hypodense compared with a normal pancreas, especially on CECT.
D. Pancreatic duct dilatation (> 2-3 mm in diameter) may be the only indirect evidence of a small neoplasm. Dilatation is more common when the neoplasm is located in the pancreatic head and can result in both CBD and pancreatic duct dilatation (“double duct” sign). This sign may also be present in chronic pancreatitis.
E. Biliary tract dilatation is more commonly seen with neoplasms in the head of the pancreas. Isolated intrahepatic biliary ductal dilatation may be seen with pancreatic cancer that has spread to the porta hepatis.
F. Local invasion is most commonly into the peripancreatic fat, but occasionally into the porta hepatis, stomach, spleen, and adjacent bowel loops.
G. Regional lymph node enlargement occurs, including nodes in the porta hepatis, paraaortic region, and area around the celiac and superior mesenteric artery axis.
H. Liver metastasis occurs as pancreatic metastases that usually are low-density lesions.