History
Most frequently, a solitary, hairless patch is noted on the scalp at birth or in early childhood. A velvety tan or orange-yellow plaque may also occur on other areas of the head and the neck.
Hormonal influences from the mother may briefly increase the prominence in an infant, whereas pubertal hormones enhance the verrucoid appearance in an adolescent.
Nevus sebaceus has a predilection for the scalp (vertex) and less commonly occurs on the face, around the ears, on the neck, or on the trunk. Nevus sebaceus occurring exclusively in the oral cavity has also been reported. [6]
Physical Examination
Nevus sebaceus passes through 3 clinically distinct stages, as follows:
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. Extensive lesions not limited to the head have been reported. [7]
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.
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. [8, 9, 10]
An unusual phenotype with large, pink, exophytic and pedunculated nodules has been reported. [11]
The most common tumors arising within nevus sebaceous are syringocystadenoma papilliferum and trichoblastoma. A rare case of hybrid follicular cyst with matrical differentiation has been also reported. [12]
Note the images below:
Nevus sebaceus manifesting as an orange-yellow plaque with a smooth or somewhat velvety surface in a 6-month-old baby.
Nevus sebaceus manifesting as a small plaque beside a scaly scalp in a 13-year-old boy.
Nevus sebaceus lesions, especially when large, may be associated with multiple internal abnormalities, similar to those reported in linear epidermal nevus syndrome. [13]
Associated problems may include intracranial masses, seizures, mental retardation, skeletal abnormalities, pigmentary changes, ocular lesions, and hamartomas of the kidney. Mediastinal lipomatosis has also been reported.
Schimmelpenning syndrome is the combination of extensive sebaceous nevi with disorders of the central nervous system, the bone, and the eye. Some of the more common abnormalities include epilepsy; mental retardation; seizures or other neurologic defects; skeletal deformities, such as vitamin D–resistant rickets, spina bifida, bone hyperplasia, or bone hypertrophy; and ocular lesions, such as ptosis, nystagmus, optic nerve hypoplasia, and oculomotor dysfunction.
A case of linear squamous cell papilloma associated with sebaceous nevus syndrome has been described in a 7-year-old boy.
Complications
Rapid, circumscribed enlargement, ulceration, or development of an exophytic nodule should raise suspicion of malignant transformation, although the development of benign appendageal tumors is considerably more common.
The most common malignancy is basal cell carcinoma, but the incidence of this tumor has been overestimated because of misinterpretation of areas of basaloid proliferation as true basal cell carcinoma. Other malignant tumors reported include eccrine, squamous, sebaceous, and apocrine carcinomas.
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Nevus sebaceus in a 4-month-old baby manifesting as nodular plaque.
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Brownish wartlike plaque in a 25-year-old patient.
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Nevus sebaceus manifesting as a bald patch in a child.
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Nevus sebaceus manifesting as an orange-yellow plaque with a smooth or somewhat velvety surface in a 6-month-old baby.
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Nevus sebaceus manifesting as a small plaque beside a scaly scalp in a 13-year-old boy.
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Linear type of nevus sebaceus.
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Mild papillomatosis of the epidermis with sebaceus gland lobules opening directly onto the epidermis.
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Mild papillomatosis at high power.
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Verrucous plaque in a 19-year-old woman.
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Verrucous plaque in a 12-year-old-girl.
