Microscopic polyangiitis. Delineation of a cutaneous-limited variant associated with antimyeloperoxidase autoantibody.

BACKGROUND

Microscopic polyangiitis is a systemic small vessel vasculitis, which, although primarily associated with necrotizing and crescentic glomerulonephritis and pulmonary capillaritis, often has cutaneous and musculoskeletal features. Microscopic polyangiitis is strongly associated with antineutrophil cytoplasmic autoantibodies, most often demonstrating a perinuclear immunostaining pattern. This pattern usually demonstrates specificity for antimyeloperoxidase autoantibodies. We report a case of microscopic polyangiitis, which, even after several years, has remained predominantly cutaneous.

OBSERVATIONS: We describe a patient with a 22-year history of cutaneous purpuric vasculitis. The lesions occur in crops at 4- to 6-week intervals and are associated with constitutional upset and elevated serologic inflammatory indexes. The antimyeloperoxidase titers closely correlate with disease activity in this patient. After close, long-term review and extensive investigations, no evidence of necrotizing and crescentic glomerulonephritis, pulmonary capillaritis, or other deep-organ involvement has been detected.

CONCLUSIONS

To our knowledge, this is the first report of a long-term evaluation of predominantly cutaneous microscopic polyangiitis and demonstrates that serologically characteristic microscopic polyangiitis may remain limited without subsequent progression to characteristic systemic involvement. This observation contributes to the understanding and characterization of the clinicopathologic spectrum of microscopic polyangiitis.