Agnogenic myeloid metaplasia with polyarteritis.

The 1st known case of agnogenic myeloid metaplasia and chronic polysynovitis is described. The arthritis, although disabling and clinically inflammatory, has not been locally invasive or destructive. The synovial fluid showed a mononuclear cell response, and the serum was hypocomplementemic and yielded cryoglobulins. The observations are consistent with an immune pathogenesis.