Review Question - QID 210903

A healthy, 32-year-old man presents to the clinic concerned that he may have melanoma. The patient states that he works outdoors as a landscaper. He recalls getting bit by mosquitoes 3 months ago while on the job. One bug bite evolved into a raised, hyperpigmented “bump” on his leg that has not gone away. He reports the spot is occasionally itchy but denies pain. He feels the lesion is larger than the original bite, but it has not grown significantly. The patient’s father died of melanoma. His mother is alive but developed breast cancer at age 49. The patient is a current tobacco smoker and has smoked 1 pack per day since age 22. He states that due to his occupation, he is in the sun a lot, but he uses sunscreen regularly. His temperature is 98.7°F (37°C), blood pressure is 115/62 mmHg, pulse is 62/min, respirations are 11/min, and oxygen saturation is 99% on room air. Upon physical exam, you note a lesion on his right leg, as shown in Figure A. The lesion feels firm, is not tender to palpation, and has no overlying scales. Which of the following is the most likely diagnosis?