What is Becker’s melanosis?

Becker’s melanosis (also known as Becker’s pigmented hairy hamartoma or Becker’s nevus) is a benign pigmented lesion that develops in the second or third decade of life with a male:female ratio of 5:1. There is no predominance of race, and one large study reported a prevalence of 0.52% in males between ages 17 and 26 years. Greater than 80% of lesions occur on the trunk, appearing as a tan to dark brown patch with an irregular border ranging in size from 100 to 500 cm2. Excess hair growth has been reported in 56% of cases. With onset in the teen years and young adulthood, Becker’s melanosis is easily differentiated from a congenital nevus and CALM of Albright’s syndrome, which are present at birth. Once fully developed, Becker’s melanosis remains stable for the life of the patient.