A male case of acute onset antimitochondrial-M2 antibody-positive autoimmune hepatitis after pulmonary thromboembolism: A case report

A male in his 50s was admitted due to epigastric pain and jaundice. His medical history included an etiology-unknown deep venous thrombus and pulmonary thromboembolism without antiphospholipid antibody positivity approximately 2 years ago. Initial liver tests showed a total bilirubin level of 7.7 mg/dL, AST of 893 IU/L, and ALT of 1217 IU/L, indicating acute hepatitis. Viral, drug-induced, and alcoholic hepatitis were excluded, but autoimmune liver disease was suspected as he tested positive for ANA and AMA-M2 antibodies. A liver biopsy performed on day 5 of admission did not show any remarkable bile duct lesions such as CNSDC, but interface hepatitis, diffuse hepatocytic necrosis, emperipolesis, and rosette formation were seen. Hence, a diagnosis of acute onset AMA-M2 positive autoimmune hepatitis (AIH) was made, and combination therapy with prednisolone and ursodeoxycholic acid was initiated, which led to normalization of liver function tests. A causal relationship between deep thrombotic diseases and AIH is not known, and male case of AMA-M2 positive AIH with acute hepatitis-like onset and a history of deep thrombosis is rare.