Nevus comedonicus

The nevus comedonicus (NC) is an uncommon variant of adnexal hamartoma whic h appears clinically as linear groups of open comedones. Its name may be a misnomer since, according to some, true comedones are not present. NC usual ly occurs by itself but may be linked with a variety of systemic findings s uch as skeletal or ocular anomalies. Although the nevus comedonicus is view ed by many as a hamartoma arising from a defective mesoderm, others conside r this lesion to be an epidermal nevus involving the hair follicle or an ap pendageal nevus of sweat ducts.