Case report
A 57-year-old woman was diagnosed with malignant lymphoma in July 2000 after a positive stool occult blood test during a physical examination, and rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone (R-CHOP) chemotherapy was administered. During the two courses of chemotherapy, blood tests confirmed abnormal liver enzyme levels. The patient was asymptomatic, no new medications were started, and there was no significant medical history. Laboratory tests revealed no signs of chronic liver hepatitis. The results of liver function tests were as follows; aspartate aminotransferase, 395 (10-42 U/L), alanine aminotransferase, 235 (13-30 U/L), alkaline phosphatase, 169 (38-113 U/L), and total bilirubin, less than 0.2 (0.4-1.5<mg/dl). Hepatic synthetic function was normal. Ultrasonography of the liver was normal, and contrast-enhanced computed tomography (CT) revealed no organic abnormalities in the liver. Prior to referral to our hospital, the patient had been suffering from anemia due to gastrointestinal bleeding. She had received RBC transfusion at another hospital; it was therefore surmised that her symptoms may be due to a transfusion-transmitted infection. The patient was screened for hepatitis A, B, and C virus, human immunodeficiency virus, herpes virus, and cytomegalovirus. The results of all the screening tests were negative. In addition, although the patient was of an age at which autoimmune diseases are common, liver autoantibody test results were normal. Therefore, autoimmune diseases such as primary biliary cirrhosis and autoimmune hepatitis were ruled out. Since the patient had a history of eating undercooked pork, we considered the possibility of hepatitis E and measured HEV-RNA, which was positive at 1.63 × 102 IU/mL. A liver biopsy was performed to confirm the diagnosis, which revealed inflammatory cell infiltration including lymphocytes and histiocytes mainly in zone 1, bile stagnation including the portal vein area, and coagulation necrosis including the appearance of eosinophils, consistent with the findings of hepatitis E. Several reports have reported the initiation dose of ribavirin for hepatitis E, with a dose adjusted on the basis of the estimated glomerular filtration rate or weight-adjusted dose (1)
The patient was started on ribavirin 400 mg with a weight-adjusted dose, and blood tests showed no apparent drug-related adverse events. After the start of treatment, the HEV-RNA became almost undetectable (Figure 1); therefore, R-CHOP therapy was resumed. Positron emission tomography/CT confirmed complete remission after six course of the chemotherapy (Figure 2).