The ANCA-associated small vessel vasculitides
ANCA are associated with a group of diseases referred to as the ANCA associated small vessel vasculitides. Included in this group are Churg-Strauss syndrome (CSS), Wegener’s granulomatosis (WG), and microscopic polyangiitis (MPA). Limited areas of necrosis (focal lesions) involving the interior walls of arterioles and small arteries characterize these diseases with overlapping involvement of medium or large vessels occurring in nearly half of the patients with microscopic polyangiitis. Involvement of the kidneys and lungs is frequent in these diseases.