Review Question - QID 109542

A 67-year-old man presents to his primary care physician after noticing a new growth on his back. His wife first saw it several weeks ago and they thought it was a scab that would resolve. They sought medical care after they realized the lesion has persisted. The patient denies any itching or pain. He has a past medical history of gastroesophageal reflux for which he takes omeprazole. He is also an active smoker with a 45-pack-year history. The patient has a family history of colon cancer in his father and a stroke in his mother. At this visit, the patient’s temperature is 98.6°F (37.0°C), pulse is 76/min, blood pressure is 128/85 mmHg, and respirations are 13/min. Cardiopulmonary and abdominal exams are unremarkable. A skin examination of his back is notable for the lesion shown in Figure A. Which of the following is the most likely diagnosis?