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Synonyms:
nevus sebaceus of Jadassohn, organoid nevus, verrucous epidermal
nevi, epidermal nevus syndrome;
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Location:
predilection for the scalp (vertex) and less commonly the face,
the neck, or the trunk;
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Clinical: most
frequently, a solitary, hairless patch is noted on the scalp at
birth or in early childhood.
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Gross:
velvety tan or orange-yellow plaque mostly on the head and the
neck.
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Nevus sebaceus
passes through 3 clinically distinct stages: 1). At birth or in
early infancy, nevus sebaceus appears as a hairless, solitary,
linear or round, slightly raised, pinkish, yellow, orange, or
tan plaque, with a smooth or somewhat velvety surface. The nevus
is usually on the scalp, often near the vertex or on the face.
2). In adolescence, the lesion becomes verrucous and nodular,
round, oval, or linear in shape, varying in length from about 1
cm to more than 10 cm. They most commonly occur as a single
lesion, but they may be multiple and extensive. 3). Later in
life, some lesions may develop various types of appendageal
tumors, such as trichoblastoma; syringocystadenoma papilliferum;
basal cell carcinoma; and, less commonly, nodular hidradenoma,
sebaceous epithelioma, apocrine cystadenoma, eccrine carcinoma,
squamous cell carcinoma, sebaceous carcinoma, spiradenoma, and
keratoacanthoma.
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Histology:
Epidermis typically reveals marked
acanthosis and surface papillation, which
resembles seborrheic keratosis. The dermis shows increased
number of mature sebaceous glands. In childhood, the sebaceous
glands in nevus sebaceous are underdeveloped, and the histologic
findings may consist of only immature hair structures. In
adolescents, the adnexal elements are more prominent, and are
represented by sebaceous hyperplasia, apocrine proliferation,
apocrine duct dilation and proliferation of eccrine glands.
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Differential diagnoses:
epidermal nevus and seborrheic keratosis, especially in
inadequate samples. Nevus sebaceus is more common. More sampling
may be necessary.
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