A 17-years-old woman with type 1 diabetes mellitus known since the age of 9 was admitted in the high-dependency unit for diabetic ketoacidosis. She had a history of poor glycemic control and many previous hospitalizations. Two years earlier, she reported the appearance of a red-brown, telangiectatic and hyperpigmented patch, localized in the pretibial skin of her left leg (Fig. 1). The lesion was well-circumscribed with erythema at the periphery. Two months before a spontaneous ulceration appeared in the middle of the lesion, apparently without any trauma.
