Microscopic polyangiitis

Definition

Necrotizing vasculitis, with few or no immune deposits, predominantly affecting small vessels (i.e., capillaries, venules, or arterioles). Necrotizing arteritis involving small and medium sized arteries may be present. Necrotizing glomerulonephritis is very common. Pulmonary capillaritis often occurs. Granulomatous inflammation is absent.

Exclusions

• Polyarteritis nodosa

Inclusions

• Microscopic polyarteritis

Index Terms