Hairy cell leukemia.

The clinical findings in 12 patients with an unusual type of leukemia have been reviewed. The leukemic cell cannot be identified with any of the normal hematopoietic cells or with any of the lymphomas and may best be referred to by the descriptive term "hairy cell", which describes its appearance, most clearly seen on phase contrast microscopy. The patients were all males and the major clinical features were enlargement of the liver and spleen, with little lymph node enlargement. Hematologic findings in most patients have been anemia and thrombocytopenia with the characteristic abnormal cells present in the peripheral blood and bone marrow. The disease most often runs an indolent course and has shown little or no response to a variety of forms of treatment.