A woman with diabetes and a sore on her leg

A 45-year-old woman with insulin-dependent diabetes mellitus presents with a sore on her right leg. She describes a long-standing history of asymptomatic lesions on her shins but had only recently injured her leg, causing the sore, which is slow to heal. Despite a 15-year history of diabetes, she has no systemic complications. She has large, well-circumscribed plaques on her anterior ...