A 22-year-old Japanese woman was found to have severe esophageal varices and then suffered from hepatic encephalopathy. She was diagnosed with Budd-Chiari syndrome (BCS) due to hepatic vein (HV) thrombosis accompanied by portal vein thrombosis without inferior vena cava (IVC) obstruction. Latent myeloproliferative neoplasm (MPN) lacking the JAK2-V617F mutation was considered to be the underlying disease. Liver transplantation was strikingly effective for treating the clinical symptoms attributable to portal hypertension. Although thrombosis of the internal jugular vein occurred due to thrombocythemia, which manifested after transplantation despite anticoagulation therapy with warfarin, the thrombus immediately disappeared with the addition of aspirin. Neither thrombosis nor BCS has recurred in more than 4 years since the amelioration of the last thrombotic event, and post-transplant immunosuppression with tacrolimus has not accelerated the progression of MPN. In Japan, IVC obstruction, which was a predominant type of BCS, is suggested to have decreased in incidence with recent improvements in hygiene. The precise diagnosis of BCS and causative underlying diseases should be made with attention to the current trend of the disease spectrum, which fluctuates with environmental sanitation levels. Because the stepwise strategy, including liver transplantation, has been proven effective for patients with pure HV obstruction in Western countries, this strategy should also be validated for utilization in Japan and in developing countries where HV obstruction potentially predominates.
