Skin, Leukocytoclastic vasculitis

Leukocytoclastic vasculitis is a hypersensitivity-related small-vessel vasculitis. Leukocytoclastic refers the accumulation of nuclear debris of neutrophils within the blood vessel walls. Sections show epidermis and dermis. The epidermis is unremarkable. Within the dermis, predominantly affecting the superficial vascular plexus, is an acute vasculitis. There is a perivascular infiltrate of neutrophils associated with leukocytoclasis and extravasated erythrocytes. The vessels show markedly reactive endothelium and there is focal destruction of the vessel wall associated with microscopic fragments of fibrin. The deeper dermis shows a mild but similar perivascular leukocytoclastic infiltrate.