Review Question - QID 109095

A 69-year-old man presents to his primary care physician for a general checkup. The patient works as a farmer and gardens in his spare time. He has a medical history of poorly managed type 2 diabetes mellitus and irritable bowel syndrome. His current medications include lisinopril, metformin, insulin, fiber supplements, and a multivitamin. On physical exam, there is a calm, obese gentleman. Inspection of the patient's scalp reveals the finding shown in Figure A. The patient is sent home and instructed to keep a blood glucose journal. Three months later, the patient returns with his glucose journal. In addition, he complains of a cut on his scalp that is not seeming to heal. The patient's glucose journal reveals an average blood glucose of 175 mg/dL. His temperature is 98.8°F (37.1°C), blood pressure is 134/86 mmHg, pulse is 80/min, and respirations are 13/min. On inspection of the patient's scalp, the finding in Figure B is noted. Which of the following is the most likely diagnosis?