DISCUSSION
Linear epidermal nevi (LEN) are congenital hamartomatous lesions of embryonal ectodermal origin. They are classified based on their main components, which can be
- Sebaceous
- Apocrine
- Eccrine
- Follicular
- Keratinocytic.
The significance of the linear configuration is that in up to one-third of patients another organ system (eg, brain, eyes, bone) will be affected. Associated neurologic problems include seizures and intellectual disability, which are caused by a variety of neuropathologic lesions.
Other forms of epidermal nevi include nevus comedonicus (associated with cataracts) and inflammatory linear verrucous epidermal nevus (ILVEN). Most often seen in early childhood on the limbs, ILVEN accounts for about 5% of all epidermal nevi.
The case patient appeared to have a mixed form, composed of epidermal and comedonal elements. Fortunately, he did not have any other associated abnormalities.
Other items in the differential include lichen striatus, wart, and koebnerized psoriasis.
Treatment for LEN is problematic, due to not only pain and scarring but also the loss of normal pigment. Options include laser, dermabrasion, and surgery. Smaller lesions can simply be excised.
TAKE-HOME LEARNING POINTS
- Linear epidermal nevi (LEN) are benign, unusual, congenital, hamartomatous tumors of embryonal ectodermal origin, which mostly manifest above the waist (ie, shoulders, trunk) in a linear configuration.
- LEN are classified according to their predominant structural element (sebaceous, eccrine, apocrine, follicular, keratinocytic).
- About one-third of all cases involve other organs, including the brain, eyes, or skeleton.
- The differential for LEN includes wart, koebnerized psoriasis, and lichen striatus.
- Treatment can be problematic, but options include laser, dermabrasion, and surgery.