Dermatology Online Journal

Epidermal Nevus
Jonathan S. Dosik M.D.
Dermatology Online Journal 7(1): 14

Department of Dermatology, New York University

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PATIENT: five-year-old boy

DURATION: Five years

DISTRIBUTION: Face, scalp, and neck

History

The patient presented at five months of age with yellow plaques on the right frontal scalp. At six months, he developed hyperpigmented verrucous papules on the right occipital scalp. In the last five years, the lesions have slowly progressed in elevation and extent but have remained localized to the right face, scalp, and neck. The lesions are not painful or pruritic, and he is developing normally.

Physical Examination

Slightly elevated, yellow plaques were present on the right cheek and right forehead and extended onto the right frontal and parietal scalp. In contiguity with these lesions were hyperpigmented, verrucous papules, which coalesced into linear plaques extending from the right occipital scalp to the right posterior neck.

Figure 1	Figure 2

Laboratory Data

A computed tomography scan of the head was normal at age six months.

Histopathology

There was papillomatous hyperplasia and hyperkeratosis of the epidermis with immature sebaceous lobules and dilated apocrine glands within the dermis.

Diagnosis

Epidermal nevus (nevus sebaceous/verrucous epidermal nevus)

Comment

Epidermal nevi are hamartomas that are characterized by hyperplasia of the epidermis and adnexal structures.[1] These nevi may be classified into a number of distinct variants, which are based on clinical morphology, extent of involvement, and the predominant epidermal structure in the lesion. Variants include verrucous epidermal nevus, nevus sebaceous, nevus comedonicus, eccrine nevus, apocrine nevus, Becker's nevus, and white sponge nevus.

Verrucous epidermal nevi consist of hyperplasia of the surface epidermis and typically appear as verrucous papules that coalesce to form well-demarcated, skin colored to brown, papillomatous plaques. Most lesions are present at birth or develop during early infancy; they enlarge slowly during childhood and generally reaching a stable size at adolescence. Lesions may be localized or diffuse. Linear configurations are common, especially on the limbs, and may follow skin tension lines, or Blaschko's lines. Histology of verrucous epidermal nevi shows hyperkeratosis, acanthosis and papillomatosis. Epidermolytic hyperkeratosis may be noted in diffuse cases, and less commonly, in localized epidermal nevi. Verrucous epidermal nevi, especially if extensive, may be associated with the epidermal nevus syndrome, a disease complex consisting of various developmental abnormalities of the skin and eyes, as well as the central nervous, skeletal, cardiovascular, and urogenital systems.[2] Rarely, malignant transformation to basal cell and squamous cell carcinomas may be seen.[3]

Nevus sebaceous includes many of the surface findings of verrucous epidermal nevus, but also contains malformations of the dermis, most prominently, hyperplasia and malpositioning of the sebaceous glands. These nevi almost always occur on the scalp or face and are present at birth as yellow, hairless, thin plaques. At puberty, in response to androgens, they tend to become raised and verrucous. Histopathologic changes consist of enlarged sebaceous lobules and apocrine glands, slight epidermal changes, and a decreased number of malformed and misoriented follicular units. The development, generally in adulthood, of a variety of benign and malignant tumors in nevus sebaceous is much more common than in verrucous epidermal nevi. The most common benign tumor is syringocystadenoma papilliferum, and the most common malignant tumor is basal cell carcinoma. The risk of basal cell carcinoma had led to the common practice of prophylactic excision of nevus sebaceous during childhood. However, a recent histopathologic review of a large series of tumors arising in nevus sebaceous has found that the majority of reported secondary basal cell carcinomas are actually benign trichoblastomas.[4]

References

1. Solomon LM, Esterly NB. Epidermal and other congenital organoid nevi. Curr Probl Pediatr 1975;6(1):1-56. PubMed

2. Rogers M, McCrossin I, Commens C. Epidermal nevi and the epidermal nevus syndrome. A review of 131 cases [see comments] J Am Acad Dermatol 1989;20(3):476-88. PubMed

3. Hohenleutner U, Landthaler M. Laser therapy of verrucous epidermal naevi. Clin Exp Dermatol 1993;18(2):124-7. PubMed

4. Cribier B, Scrivener Y, Grosshans E. Tumors arising in nevus sebaceus: A study of 596 cases. J Am Acad Dermatol 2000;42(2 Pt 1):263-8. PubMed

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