Derm Dx: A nodule on the scalp since childhood

A 39-year-old woman requests removal of a growth on her scalp. She was born in Nigeria and emigrated to the United States at the age of 26 years. She first noticed the lesion at age 10 years, at which time it was diagnosed as a wart. Since then, the lesion has enlarged slowly but has remained asymptomatic. Examination reveals a ...