Comedo naevus of the palm--a sweat duct naevus?

A 9-year-old boy is described with keratotic pits on the left palm, present since birth, which clinically resembled those seen in comedo naevus. Histology and scanning electron microscopy of skin surface replicas showed the lesions to be large, abnormal sweat ducts. It is suggested that comedo naevi are not necessarily pilosebaceous in origin and that in our case the term sweat duct naevus may be more appropriate.