Disseminated Mycobacterium kansasii infection complicating hairy cell leukemia.

Mycobacterium kansasii was isolated from the spleen of a patient with ""hairy cell leukemia'' (HCL) who had caseating necrosis in the spleen and in the liver. The disseminated infection in this patient suggests a cellular immunity deficit. Despite intensive investigations, the nature of the cell of origin in HCL remains unknown.