Section 10. Benign Appendageal Proliferations

A nevus sebaceus is a solitary, well-circumscribed, yellow-orange hairless plaque located on the face or scalp that is a hamartoma of follicular, sebaceous, and apocrine origin.

Synonyms Nevus sebaceus of Jadassohn, organoid nevus.

Epidemiology

Age Usually present near birth. May appear in childhood or adulthood.

Gender M = F.

Prevalence Uncommon.

Genetics Usually sporadic, rare familial forms reported.

History

A nevus sebaceus is typically present near birth and has two stages: prepubertal (infantile phase, see Fig. 10-1A) and pubertal (adolescent phase, see Fig. 10-1B).

Physical Examination

Skin Findings

Type Hairless plaque surface may be velvetlike, verrucous, or papillomatous.

Color Yellow, yellow-brown, orange, pink.

Size Few millimeters to several centimeters.

Shape Round, oval, or linear.

Distribution Head and neck.

Arrangement Solitary, rarely, multiple lesions have been reported.

General Findings

Typically there are no systemic symptoms. In the scalp, the lesion remains hairless. Rarely, extensive lesions can be associated with ocular, CNS, or skeletal abnormalities.

Differential Diagnosis

The differential diagnosis includes other appendageal tumors; smaller lesions can resemble warts.

Laboratory Examination

Dermatopathology Infancy: numerous immature sebaceus glands and cords or buds of undifferentiated hair follicles. Adult: papillomatous hyperplasia of the epidermis with hyperkeratosis and hypergranulosis. There are also typically ectopic apocrine glands located deep in the dermis.

Course and Prognosis

Nevus sebaceus tend to grow slowly and become thicker and more papillomatous with age. Approximately 10% may have neoplastic changes that manifest as nodules or ulcers within the lesion: trichoblastoma, trichilemmoma, syringocystadenoma papilliferum (Fig. 10-2) are the most common neoplasms. Other possible growths include sebaceous adenoma, apocrine adenoma, poroma, basal cell carcinoma, and squamous cell carcinoma.

Management

Nevus sebaceus lesions before puberty can be observed regularly for any signs or symptoms of neoplastic change. And after puberty, although there is an increased risk of neoplasms such as syringocystadenoma or ...