Derm Dx: Hyperkeratotic lesions of the palms and soles

A 58-year-old African American man presents with multiple hyperkeratotic lesions on his palms and soles. The lesions are discrete, firm, and slightly elevated, ranging in diameter from 2 to 5 mm. The condition first manifested at age 16 and requires constant paring because pressure induces pain. He states that his mother and one sister are similarly affected.