Clinical problems in hairy cell leukemia: diagnosis and management.

Patients with HCL are subject to a variety of medical problems. Many of these complications are caused by the cytopenias and splenomegaly produced by proliferating neoplastic cells. Infection is a common cause of morbidity in HCL, but it is not clear whether there is an inherent defect in the immune system. The incidence of infection is related to neutropenia and is increased by the administration of cytotoxic drugs and corticosteroids; such drugs should be used cautiously in these patients. Opportunistic or unusual pathogens occur frequently in HCL, but recovery from such infections is the rule if the diagnosis is made early. Marrow hypoplasia is not infrequently seen and may present diagnostic difficulties. Such patients may have a lower tumor burden and clinically milder anemia. Hemorrhagic complications are unusual in HCL, though many patients have platelet function abnormalities. Other medical problems occur with increased frequency in HCL, and failure to recognize them leads to increased morbidity in this disease. Autoimmune disease is seen in up to one fourth of patients. It takes the form of self-limited skin and joint disease, or a more progressive, systemic of patients. It takes the form of self-limited skin and joint disease, or a more progressive, systemic vasculitis. Both forms can usually be treated with splenectomy or corticosteroids, but alkylating agents can also be used successfully. Bone disease is usually localized and responds well to radiotherapy. Other problems such as amyloidosis, multiple myeloma, and paraproteinemia are uncommon in HCL.