Intravascular Large B-cell Lymphoma Associated With Hemophagocytosis as a Cause of Fever of Unknown Origin: A Review of Literature.

A 53-year-old woman was hospitalized due to a fever of unknown origin for three weeks. Given the presence of fever and fatigue, the laboratory findings, and a bone marrow biopsy confirming hemophagocytic lymphohistiocytosis (HLH), a hematological malignancy was suspected. Peripheral lymphocytic typing, bone marrow biopsy, and imaging could not identify an underlying cause of HLH. Therefore, an abdominal wall deep skin biopsy was performed, showing an intravascular large B-cell lymphoma (IVLBCL). Intravascular large B-cell lymphoma should be considered in all patients with fever of unknown origin, especially in the context of HLH. Diagnosis of IVLBCL requires a deep skin biopsy or a biopsy of an affected organ.