Abstract
We report the case of a patient with recurrent fever of unknown origin (FUO) with prominent back pain, hepatosplenomegaly, and abdominal/pelvic adenopathy suggesting lymphoma. A bone biopsy showed histiocytic infiltration. Studies for lymphoma were negative, but immunohistochemical stains were diagnostic of Erdheim–Chester disease (ECD). ECD should be included as a rare cause of recurrent FUO with bone involvement.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.