Extrahepatic portal venous obstruction of different pathogenesis in pancreatic diseases: reports of 4 autopsy cases with chronic pancreatitis and pancreatic carcinoma

Four autopsy cases of extrahepatic portal venous obstruction associated with pancreatic diseases, 1 case of pancreatitis and 3 cases of pancreatic carcinoma, are presented. The pathogenesis of portal obstruction was different in each case; old thrombosis with recanalization due to chronic pancreatitis with pseudocysts formation in 1 case, fresh thrombosis due to intraportal venous catheterization for pancreatic carcinoma in 1 case, fresh thrombosis probably due to pancreatitis accompanying pancreatic carcinoma in 1 case, and direct invasion of pancreatic carcinoma into the portal vein in the remaining 1 case. Morphologic evidence for portal hypertension was present in each case. In the pancreatitis case and one pancreatic carcinoma case with portal tumor invasion, both of which had chronic portal obstruction, there were many thin-walled vascular channels (cavernous transformation) around the occluded portal vein. Their endothelia were positive for factor VIII-related antigen and Ulex europaeus lectin I, implying that these vessels were hepatopetal blood vascular collaterals. It was shown that pancreatic diseases resulted in portal venous obstruction by several different mechanisms and chronic portal obstruction in pancreatic diseases led to the formation of hepatoperal blood vascular collaterals.