Necrobiosis lipoidica in a diabetic intravenous drug user.

Necrobiosis lipoidica occurs most commonly on the lower extremities in patients with diabetes; lesions typically occur in the pretibial region. Although the pathogenesis of necrobiosis lipoidica remains unclear, both external trauma and vascular damage have been proposed as contributing to the development of this disorder. We report polarizable foreign material in small blood vessels and multinucleated histiocytes in lesions of necrobiosis lipoidica. This phenomenon occurred in a patient who was both diabetic and an intravenous drug user.