A Novel Case of Chronic EBV Infection Mimicking Polymyositis with Hemophagocytic Syndrome

Background: The combination of EBV associated myositis and hemophagocytic syndrome is very rare and is lacking sufficient clinical study. The authors describe a novel case of myositis and hemophagocytic syndrome in a 17 -year-old boy with chronic EBV infection. Methods: Hematological and immunological blood investigation, bone marrow aspirate, labial and muscle pathological test and immunohistochemistry staining of Epstein-Barr virus-encoded small RNA (EBER) were performed. Results: The patient was started on prednisolone and methotrexate for treatment of the myositis and his symptoms decrease for 2 months and rapidly progressed with worsening cytopenia, liver function tests, and coagulation profile. The patient was treated empirically with intravenous antibiotics and human immunoglobulin G. He developed fulminant hemophagocytic syndrome and passed away due to multiorgan failure 14 months after the onset of the disease. Conclusions: Performing a limited IHC with EBER will be helpful to diagnose EBV infection involving muscle. EBV infection as a prognostic factor of myositis needs further studies. (Clin. Lab. 2022;68:xx-xx. DOI: 10.7754/Clin.Lab.2021.210810)