[A case of portal-systemic shunt encephalopathy due to congenital portal vein hypoplasia presenting with abnormal cerebral white matter lesions on the MRI].

A 49-year-old woman, without any past history of liver diseases and blood transfusion, was admitted to our service because of somnolence, and flapping tremor. Neurologically, she was drowsy and disoriented. She had bilateral pyramidal tract signs and flapping tremor. Although the laboratory examination showed marked hyperammonemia (217 micrograms/dl), neither abdominal CT nor liver biopsy showed any evidence of liver cirrhosis. An abdominal angiography showed portal vein hypoplasia associated with the portal-systemic shunt. A T2-weighted MRI showed the high intensity areas in the bilateral deep cerebral white matter, and the posterior limbs of the bilateral internal capsules. This is a rare case of portal-systemic shunt encephalopathy due to congenital portal vein hypoplasia presenting with abnormal cerebral white matter lesions on the MRI.