Left, The lateral calf has deep cutaneous ulcers, resembling pyoderma gangrenosum. Skin ulcers arise as a result of a small- and medium-sized vessel vasculitis in the subcutaneous fat and dermis.
Right, The abdomen of the same patient with superficial venous collaterals arising as a result of inferior vena caval thrombosis. Vascular inflammation in BehÁetís disease may involve large segments of the superior and inferior vena cavae, resulting in thrombotic occlusion.
In this patient, a skin biopsy adjacent to an area of ulceration showed dermal foci of dense neutrophilic infiltration with necrosis and vasculitis.