Abstract
The clinical features are described of disseminated atypical mycobacterial infection of the subcutaneous tissues occurring in a patient 3 yr after the diagnosis of hairy cell leukemia. Skin biopsy identified the causative organism as an atypical mycobacterium of the M. avium-intracellulare-scrofulaceum (MAIS)complex. In vitrostudies showed that the patient had impaired mononuclear cell phagocytosis. These findings lend support to the hypothesis of a specific defect of immunity in hairy cell leukemia.