[Polyarthritis revealing hairy cell leukemia].
A female patient simultaneously developed hematologic evidence of hairy cell leukemia and marked but short-lived inflammatory involvement of a number of joints. Both these groups of symptoms resolved simultaneously and rapidly under alpha-2 interferon therapy. This course suggests that the arthritis was a rheumatologic manifestation of the hematologic disease. The concomitant occurrence in this patient of arthritis, splenomegaly and leukopenia was suggestive of Felty syndrome: these two conditions need to be differentiated.