Melanoma Quiz: Ace Your Exams

A 47-year-old man presents to the dermatology clinic with concerns about a pigmented lesion on his left upper arm. He mentions that he first noticed the lesion about 6 months ago, but in the past two months, it appears to have grown and darkened in color. He works as a construction worker and often spends prolonged periods outdoors without sun protection. Past medical history is significant for hypertension controlled with hydrochlorothiazide. Family history is noncontributory. Temperature is 36.8°C (98.2°F), blood pressure is 130/85 mm Hg, pulse is 72/min, respiratory rate is 16/min, and oxygen saturation is 99% on room air. Skin examination reveals a 1.5 cm asymmetric lesion with an irregular border and with a number of variable colors. An excisional biopsy of the lesion reveals atypical melanocytes with hyperchromatic nuclei with a Breslow thickness of 0.7 mm, without ulceration, along with inadequate margins. There is no evidence of regional lymphadenopathy on examination. Which of the following is the best next step in management?