A case of hepatic epithelioid hemangioendothelioma with features resembling those of acute-onset autoimmune hepatitis that was undiagnosed before liver transplantation.

Hepatic epithelioid hemangioendothelioma (HEHE), which is extremely rare, is considered to have a malignant grade between that of hepatic hemangioma and that of hepatic hemangiosarcoma; however, some cases progress so quickly that they present with portal hypertension. We report the case of a woman with findings similar to those of acute-onset autoimmune hepatitis (AIH) that was not diagnosed before liver transplantation. The patient presented with jaundice and ascites. A hematological examination revealed negative tumor markers, high IgG levels, and negative hepatitis virus markers. Computed tomography findings of the liver showed map-like signs characteristic of acute-onset AIH. Despite some response, immunosuppressive drugs such as prednisolone, cyclosporine, and mycophenolate mofetil did not improve liver failure, and she underwent liver transplantation after 200 days of treatment. The explanted liver exhibited white areas that extended in a map-like manner and were occupied by fibrous stroma. Tumors with WWTR1-CAMTA1 gene fusion were recognized and diagnosed as HEHE. Although a histological examination is essential, a percutaneous liver biopsy could not be performed preoperatively because of the presence of ascites. Furthermore, the rarity of the disease, similarity of imaging findings with non-neoplastic patterns, and serological findings made it difficult to differentiate this case from acute-onset autoimmune hepatitis.