Derm Dx: A dark lesion on the thigh

The patient is a 62-year-old Caucasian man referred for evaluation of a lesion on his left thigh. The growth has been present about 2 years and is asymptomatic. He has a history of basal carcinoma removed from his nose 1 year ago. Examination reveals a 1.0-cm slightly elevated nodule with dark pigmentation and a somewhat irregular border. Extensive sun damage ...