P 086 The possible role of fat cells in the pathogenesis of erythema nodosum-like lesions of Behçet's disease: an immunoelectron microscopic study

Abstract

Despite the frequency of small vessel vasculitis in skin lesions of Behçet's disease (BD), BD is classified as a neutrophilic dermatosis.Our goal was to determine whether the various cutaneous manifestations of BD are secondary to cutaneous vasculitis.Twenty-three specimens with histologically proven necrotizing vasculitis from 20 of 42 patients with BD were investigated.The cutaneous vasculilitic manifestations were characterized as erythema nodosum-like eruptions, palpable purpura, hemorrhagic blisters, infiltrated erythema, Sweet's syndrome-like eruptions, papulopustular lesions, and extragenital ulcerations. Combinations of various skin lesions were commonly seen in the same patient. Venous vessels in the entire dermis to the subcutis were affected with sparing of arterial vessels from middermis to subcutis. Histologic features included leukocytoclastic vasculitis in seven and lymphocytic vasculitis in 13 patients with extensive to focal localized fibrinoid necrosis of vessel walls.Cutaneous vasculitis in BD is predominantly venulitis or phlebitis. Approximately half (48%; 20 of 42) of BD patients with cutaneous lesions had either lymphocytic (31%; 13 of 42) or leukocytoclastic vasculitis (17%; 7 of 42). We suggest that BD be considered as a vasculitis-associated disease separate from the neutrophilic dermatoses.