Becker's naevus and segmental naevus depigmentosus: an example of twin spotting?

A 12-year-old girl presented with a 1-year history of a Becker's naevus involving the right posterior thigh and gluteal area. In addition, three hypopigmented macules of naevus depigmentosus distributed in a segmental pattern on the medial aspect of the right posterior thigh had been present since birth. We suggest that their unusual coexistence in close proximity may represent an example of twin spotting.