Epstein-Barr Virus (EBV)-induced B-cell Lymphoproliferative Disorder Mimicking the Recurrence of EBV-associated Hemophagocytic Lymphohistiocytosis.

We describe the case of a 23-month-old male infant with Epstein-Barr virus (EBV)-associated lymphoproliferative disorder, which mimicked the recurrence of EBV-associated hemophagocytic lymphohistiocytosis. Chemotherapy with dexamethasone, etoposide, and cyclosporine resolved fever, hepatosplenomegaly, and pancytopenia. However, on day 81 of illness, the patient developed similar symptoms. Plasma EBV-DNA levels markedly increased again, but no T-cell clonality was observed. B cells were identified to be infected with EBV. He was successfully treated with rituximab, dexamethasone and etoposide. When recurrence of EBV-associated hemophagocytic lymphohistiocytosis is suspected, performing tests to identify the infected cells will enable accurate understanding of the clinical condition, resulting in proper treatments.