A Case of Portal Vein Thrombosis Induced by Congenital Protein C Deficiency

Abstract

A 40-year-old man was referred to our hospital for investigation and treatment of abdominal pain. A dynamic computed tomography scan showed extensive intrahepatic thrombosis in the main trunk of the portal vein and the mesenteric vein. The patient was treated with freeze-dried human antithrombin III concentrate for 15 days, and the thrombus shrunk in size. As maintenance treatment, we administered warfarin and the thrombus did not increase. Liver biopsy showed mild fibrosis and no evidence of idiopathic portal hypertension. We found decreased protein C activity in the blood, which suggested the portal vein thrombosis was due to a protein C deficiency. Analysis of the protein C gene (PROC) mutation revealed a heterozygous stop-gain variant (p.Trp2*), confirming the diagnosis of congenital protein C deficiency. In cases of noncirrhotic or non-neoplastic portal vein thrombosis, it is important to check not only for liver disease but also for blood coagulation disorders.