Persistent Legionnaire's disease in an adult with hairy cell leukemia successfully treated with prolonged levofloxacin therapy.

Legionnaire's disease (LD) manifests most commonly as an atypical community acquired pneumonia (CAP) with systemic extrapulmonary manifestations. Disorders associated with impaired cell mediated immunity (CMI) are particularly predisposed to LD. Hairy cell leukemia (HCL) is a rare B-cell lymphoproliferative leukemia associated with decreased CMI. LD has only rarely been reported in HCL. We present a most interesting case of persistent LD in a elderly male with HCL who required prolonged antibiotic therapy.