Hairy cell leukemia presenting as a lupus-like illness

We describe a young Hispanic man who presented with features suggestive of a diagnosis of systemic lupus erythematosus. Eventually, a bone marrow biopsy was performed, and it revealed the presence of hairy cell leukemia. This case of a lupus-like syndrome should be added to the list of reported rheumatic syndromes that are associated with hairy cell leukemia.