Peripancreatic lymphatic invasion by pancreatic carcinoma: evaluation with multi-detector row CT.

Peripancreatic lymphatic networks are frequently involved in pancreatobiliary carcinoma, affecting the prognosis. However, little attention has been paid to CT imaging of normal and pathological conditions of peripancreatic lymphatic networks. We evaluated multi-detector row CT (MDCT) images of peripancreatic lymphatic networks invaded by pancreatic carcinoma and compared them with those of normal peripancreatic lymphatic networks using imaging reconstruction every 1 mm with a multiplanar reformation technique. Apart from the region around the pancreatic body and tail, normal peripancreatic lymphatic networks were detected as "linear structures" on MDCT. However, peripancreatic lymphatic invasion by pancreatic carcinoma was frequently identified as "reticular," "tubular," or "soft tissue mass" appearances in the peripancreatic fat tissues. Peripancreatic lymphatic invasion by pancreatic carcinoma was more frequently detected around the common hepatic artery, celiac artery, superior mesenteric artery, and left para-aortic area. Depending on the tumor location, positive peripancreatic lymphatic invasion was most frequent at the area around the common hepatic artery in the head region and at the area around the celiac artery in the body and tail regions. Knowledge of CT imaging of normal and pathological peripancreatic lymphatic networks is essential for determining the accurate staging of pancreatic carcinoma.