The association of hairy cell leukemia with unusual immunologic disorders.

Hairy cell leukemia is a rare disease, probably of B-lymphocyte origin, that has been reported to rarely occur with polyarteritis nodosa. The records of 31 patients with hairy cell leukemia were reviewed for an association with other disorders of the immune system; such an association was found more often than previously suspected. Four cases are discussed--one with hepatitis B surface antigen-positive polyarteritis nodosa and another with an IgA (kappa) monoclonal gammopathy and amyloidosis of the kidney, liver, and small bowel. The other two patients had cutaneous vasculitis, one of which was a rare form of leukocytoclastic angiitis--erythema elevatum diutinum. Because the number of patients in this study is small, it is impossible to say whether the association of hairy cell leukemia with any of these immunologic disorders adversely affects survival.