Severe fever with thrombocytopenia syndrome mimicking intravascular lymphoma.

A 63-year-old woman was admitted to our hospital, because of a high fever and general malaise which had persisted for several days. Laboratory findings showed leucopenia, thrombocytopenia, and abnormal liver functions. A bone marrow smear revealed hemophagocytosis. Since a diagnosis of intravascular large B cell lymphoma was strongly suspected, a random skin biopsy was performed but revealed no evidence of malignant lymphoma. She was treated with steroids, blood product transfusions, and antibiotics, and then gradually recovered. The severe fever with thrombocytopenia syndrome (SFTS) viral genome was detected in her serum obtained in the acute phase. Therefore, the final diagnosis was SFTS, which is among the major causes of hemophagocytic syndrome.