The final common pathway of pancreatic venous drainage is via the portal vein, which receives venous blood from the superior mesenteric vein and the splenic vein.  Venous drainage of the body and the tail of pancreas drain into the splenic vein and then into the portal vein which takes the blood to the liver.  The head of the pancreas drains into tributaries of the gastroepiploic vein, gastric vein, superior mesenteric vein, and portal vein.

Venous drainage of  the body – small venules of the pancreas
In this CT the small venules draining the pancreas can be seen throughout the body and tail of pancreas in this early arterial-venous phase.  Arches of venules connect with a larger vein that runs the length of the body of the pancreas.

25235 Courtesy Ashley Davidoff MD

Splenic vein and portal vein
In this CT scan the intimate posterior relationship of the splenic vein and portal vein tho the body of the pancreas is exemplified.  The pancreatic venous system of the body and tail drain into the splenic vein and then to the liver via the portal vein.

25235 Courtesy Ashley Davidoff MD