Antineutrophil cytoplasmic autoantibody-associated vasculitis presenting as Sjögren's syndrome.

A 63-year-old woman, in whom a diagnosis of Sjögren's syndrome was initially made, proved to have systemic vasculitis with salivary gland involvement and necrotizing and crescentic glomerulonephritis. Antineutrophil cytoplasmic autoantibodies (ANCA) against myeloperoxidase were positive. ANCA-associated vasculitis should be considered in the differential diagnosis of Sjögren's syndrome. A positive finding on immunoassay for ANCA against myeloperoxidase or proteinase 3 may help establish the diagnosis.