Nevus sebaceus -5 Interesting Facts

Nevus sebaceus 

1. The diagnosis of Nevus sebaceous (NS) is usually made based on the congenital nature of the lesion, history, anatomic location, and clinical appearance.
2. Serial surveillance is an option unless there is a history of recent growth in the lesion. If there is concern for a secondary malignant neoplasm in the lesion, biopsy and/or removal are necessary.
3. A complication of NS that occurs in later life is the development of a secondary neoplasia, such as basal cell carcinoma, within the lesion. The lifetime risk for the development of secondary neoplasms in NS is probably less than 10%, but some dermatologists prefer complete removal for this reason.
4. Numerous secondary neoplasms have been reported to occur in NS, including syringocystadenoma papilliferum (benign sweat gland tumor), trichoblastoma (benign hair follicle tumor), trichilemmoma (benign hair follicle tumor), and sebaceoma (benign sebaceous gland tumor). A relatively recent 18-year review in Detroit found basal cell carcinoma arose in about 1% of excised cases. The true incidence of basal cell carcinoma in NS is difficult to estimate because many cases in the literature probably represent benign trichoblastomas that are histologically similar to basal cell carcinoma.

Terminology

• Nevus sebaceus (of Jadassohn), also known as organoid nevus, is a common hamartomatous malformation of unknown cause. As a hamartoma, the normal structures of the skin (epidermis, dermis, hair, sweat glands, and sebaceous glands) are present but with abnormal hypertrophy, hyperplasia, and organization.

Etiology and Risk Factors

What causes this condition?

• Nevus sebaceus (NS) occurs sporadically; the condition is found in about 0.3% of the population. Histologically, NS is composed of an acanthotic epidermis with papillomatosis, with abnormal and disorderly growth of the sebaceous glands, hair follicles, eccrine sweat glands, and apocrine sweat glands.
• NS affects all ethnic backgrounds with equal frequency. Men and women are equally affected.

Diagnosis

Approach to Diagnosis

• The diagnosis of Nevus sebaceus is usually made based on the congenital nature of the lesion, history, anatomic location, and clinical appearance.

Workup

Physical Examination

• Figure 1. Remarkably papillomatous nevus sebaceus with focal hemorrhage sebaceus in a neonate.(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
• Figure 2. Extensive nevus sebaceus of the scalp and face. This infant is at risk for epidermal nevus syndrome.(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)
• Figure 3. Linear patch of alopecia in an adolescent caused by nevus sebaceus that has become subtly papillomatous and increasingly yellow after puberty.(From the Fitzsimons Army Medical Center Collection, Aurora, CO.)

• Most Nevus sebaceus (NS) occurs on the scalp (~50%), followed by the face (~40%) and neck (~6%), but NS can occur just about anywhere on the body.
• Typically, NS proceeds through three stages:
  • Neonatal phase—presents as a patch of hair loss that is often linear. Because of maternal hormones, the lesions are often indurated, variably papillomatous, and yellowish in color because of the hypertrophy of the sebaceous glands.
  • Childhood phase—maternal hormone levels diminish, the sebaceous gland component involutes, and the lesion flattens, leaving a linear patch of hair loss with a slightly yellow color.
  • Adolescent and adult phase—as the androgen levels rise after puberty, the sebaceous glands again accumulate lipid, and the lesions become more yellow and papillomatous.
• Patients with large and extensive NS may have epidermal nevus syndrome, which includes seizures, mental retardation, various structural abnormalities, and ophthalmologic abnormalities.

Diagnostic Procedures

• Occasional cases of Nevus sebaceus (NS) may be difficult to distinguish from simple epidermal nevi. In problematic cases, a punch biopsy or incision biopsy should be performed. Histologic examination is usually diagnostic. Shave biopsies are rarely diagnostic and are discouraged.

Treatment

Approach to Treatment

• Serial surveillance is an option unless there is a history of recent growth in the lesion. If there is concern for a secondary malignant neoplasm in the lesion, biopsy and/or removal are necessary.

Treatment Procedures

• Surgical excision is the consensus treatment of choice if the lesion is concerning or if the patient chooses this, but the timing of any excision procedure is controversial and is not standardized.

References

1.Jensen AL, Florell SR, Vanderhooft SL, Bale AE. Basal cell carcinoma arising in a nevus sebaceus in a child with facial trichoepitheliomas. Pediatric dermatology. 2011;28(2):138-141.

Reference

2.Cribier B, Scrivener Y, Grosshans E. Tumors arising in nevus sebaceus: A study of 596 cases. Journal of the American Academy of Dermatology. 2000;42(2 Pt1):263-268

Reference

3.Rosen H, Schmidt B, Lam HP, Meara JG, Labow BI. Management of nevus sebaceous and the risk of Basal cell carcinoma: an 18-year review. Pediatric dermatology. 2009;26(6):676-681.

Reference