Hairy cell leukemia: a review.

Hairy cell leukemia is a chronic but steadily progressive malignancy usually of older males. Clinically, patients present with splenomegaly and/or cytopenia. The diagnosis is made by demonstration of the hairy cell in Wright's-stained peripheral blood and in bone marrow and by the characteristic histologic findings in the bone marrow biopsy and spleen sections. Infection is the most significant problem complicating the course of patients with hairy cell leukemia and the role of granulocytopenia and/or monocytopenia is undoubtedly substantial. Splenectomy has produced an objective response in improving hematologic parameters in a large number of patients and may prolong survival in those patients who respond. The precise nature of hairy cells remains unknown. The cells exhibit features of both monocytes and B-lymphocytes in morphologic, cytochemical, immunologic and functional studies. A more complete understanding of the monocytic and lymphocytic stem cells and their maturation may provide insight into the origin of the hairy cell.