This patient has a 2-year history of red plaque with a yellow atrophic center on the leg, which has ulcerated over the past 3 months. There is a strong family history of diabetes mellitus.
The patient has necrobiosis lipoidica, a condition associated with a personal or family history of diabetes mellitus. The waxy, atrophic appearance of the lesion, with its yellow center, is diagnostic; ulceration is a late complication.
The presence of necrobiosis does not confirm the diagnosis of diabetes. In some patients with this condition, overt diabetes never develops, but one must constantly be on the lookout for this eventuality. High-potency corticosteroids may be useful for treating early lesions.