History:

A 28-year-old man presented with a linear lesion on the side of the neck. The lesion has been present since early childhood and consists of closely set, papillomatous, hyperkeratotic, dark-coloured papules on one side of the neck (unilateral). There was neither pruritus nor erythema. No associated skeletal or neurological defects were found. 

Linear epidermal nevus (Verrucous nevus) may be either localized or systematized.  It may be located anywhere on the head, trunk, or extremities. Being located on only one side of the patient, it is often referred to as nevus unius lateris.