ABSTRACT
Vasculitis associated with antineutrophil cytoplasmic autoantibodies (ANCAs)
manifests as a spectrum of clinicopathologic syndromes including microscopic
polyangiitis, Wegener’s granulomatosis, Churg-Strauss syndrome, and organ-
limited disease (Tables 1 and 2) (1,2). Microscopic polyangiitis is characterized
by systemic small-vessel vasculitis and no evidence for granulomatous inflam-
mation (3). Wegener’s granulomatosis has small-vessel vasculitis that is indis-
tinguishable from the small-vessel vasculitis of microscopic polyangiitis, but in
addition, it has necrotizing granulomatous inflammation, which most often
affects the upper and lower respiratory tracts (3). Churg-Strauss syndrome has
small-vessel vasculitis and necrotizing granulomatous inflammation with the
additional defining features of asthma and blood eosinophilia (3). However, it is
important to note that limited forms of Wegener’s granulomatosis and Churg-
Strauss syndrome occur, for example, limited to the respiratory tract, which are
less likely to have circulating ANCAs in the absence of systemic vasculitis and
glomerulonephritis (4-6).
