Approach to non-healing wounds Quiz: Ace Your Exams

A 55-year-old man presents to the office for evaluation of a wound that has been present on his right ankle for two months. He has had swelling of both legs and wounds at the same spot in the past, but they resolved without treatment. This time, his wound started as a small area of erythema, but over the ensuing weeks, it has widened in diameter and occasionally crusts over. The patient has not had fevers or chills. His past medical history is notable for poorly controlled insulin-dependent diabetes mellitus (IDDM) with a recent Hemoglobin A1c of 8.2. His BMI is 36 kg/m². He has not experienced any cramping pain while walking or leg pain in the middle of the night. He can walk several blocks without pain in his lower extremities. Vital signs are within normal limits. On exam, there is a 4cm ulcer on the medial malleolus of his right lower extremity that has granulation tissue at the base. There is clear drainage from the wound. There is surrounding reddish-brown skin discoloration but no signs of infection. Both legs have bilateral 2+ pitting edema to the mid-calves and multiple reddish-brownish spots. Dorsalis pedis and posterior tibialis pulses are 2+ bilaterally.  Which of the following is the most likely diagnosis?