Epidermal Nevus

 Localized, wart-like variants, solitary or multiple



• Nevus unius lateris
image Long, linear lesions on unilateral extremities

• Ichthyosis hystrix
image Large, bilateral lesions on trunk




Etiology/Pathogenesis




• Epidermal nevus syndrome includes neurological, ocular, and skeletal abnormalities


Clinical Issues




• Common sites include neck, trunk, and extremities

• May present together with nevus sebaceus, woolly hair nevus, and nevus comedonicus

• Associated with number of diseases and syndromes; look for other clinical findings

• Small lesion can be excised, larger lesions can be treated by laser or cryotherapy


Microscopic




• At least 10 different patterns, > 1 pattern can coexist in single lesion

• Common pattern includes hyperkeratosis with papillomatosis and acanthosis

• Inflammatory linear verrucous epidermal nevus is considered subtype of epidermal nevus


Top Differential Diagnoses




• Seborrheic keratosis

• Acanthosis nigricans

• Confluent and reticulated papillomatosis of Gougerot and Carteaud

• Organoid nevus (nevus sebaceous)

image
Hyperpigmented Epidermal Nevus
An example of an epidermal nevus exhibits hyperpigmented, curvilinear, mammillated plaque image on the anterior, midline neck of a girl. (Courtesy J. Finch, MD.)


image
Classic Histology of Epidermal Nevus
Epidermal nevus shows orthokeratotic hyperkeratosis image overlying epidermal papillomatosis image. Note hyperpigmentation in the basal keratinocytes. (Courtesy C. Cockerell, MD.)

image
Hypopigmented Epidermal Nevus
In this example of epidermal nevus in another child, a cauliflower-like, hypopigmented, and exophytic tumor clinically resembles a wart. Note the finger-like projections image. (Courtesy J. Finch, MD.)

image
Histology Resembles Seborrheic Keratosis
Under low magnification, prominent orthokeratotic hyperkeratosis image (scale without nucleated cells) and papillomatosis image (church spire-like acanthosis) are constant features of epidermal nevus.


TERMINOLOGY


Synonyms




• Nevus verrucosus: Localized, wart-like variants, solitary or multiple

• Nevus unius lateris: Long, linear lesions on unilateral extremities

• Ichthyosis hystrix: Large, bilateral lesions on trunk


Definitions




• Developmental malformation of epidermis with hyperplasia of keratinocytes

• Specific entity that does not include adnexal malformations or appendageal tumors, such as organoid/sebaceous nevus


ETIOLOGY/PATHOGENESIS


Epidermal Nevus Syndrome




• Epidermal nevi (usually extensive) with
image Neurological abnormalities (epilepsy, mental retardation)

image Ocular abnormalities (cataracts)

image Skeletal anomalies (kyphoscoliosis, limb hypertrophy)

• Various systemic cancers at young age


Other Associations




• Polyostotic fibrous dysplasia

• Proteus syndrome

• Phakomatosis pigmentokeratotica


CLINICAL ISSUES


Epidemiology




• Age
image Usually present at birth; develops during early childhood or can be seen in adulthood

Apr 24, 2017 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Epidermal Nevus
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