Nevus sebaceous is a congenital hamartoma that may be present on the scalp or face of children. Here are four things parents need to know about nevus sebaceous.
What is a hamartoma?
"Hamartoma" isn't a well-known word outside of medical circles, so it's normal to be confused when your child's doctor uses this word. Simply, a hamartoma is a benign growth that looks like a tumor. The tumor-like lesion is made up of tissues that are normally present in the affected area of the body, but the cells are mixed up abnormally, rather than being where they're supposed to be.
Nevus sebaceous lesions are comprised of cells that should make up the hair follicles, sebaceous (oil-producing) glands, and apocrine (sweat) glands, but have instead clumped together into a tumor-like mass.
What are the signs of nevus sebaceous?
Nevus sebaceous generally presents as a single, well-defined lesion on the face or the scalp. In rare cases, multiple lesions can be present.
The lesion's appearance will change over time. At first, the lesion will be hairless, smooth, and slightly raised. This early lesion may be pink, tan, or even orange.
When your child reaches adolescence, the lesion will take on a new appearance. At this point, the lesion becomes warty and lumpy. These advanced lesions can be as large as 10 centimeters long, so they can cause a lot of cosmetic distress.
What causes nevus sebaceous?
Researchers think that nevus sebaceous is caused by mutations in the genes that are responsible for cell growth, HRAS or KRAS. These mutations are believed to be postzygotic, which means that the genes mutate on their own and are not inherited in mutations from the parents.
How is nevus sebaceous treated?
Nevus sebaceous is treated with surgery. While the lesion is typically harmless, studies have shown that they can become cancerous in rare cases. Just to be safe, the lesion will need to be removed, though the timing of this surgery is flexible.
To remove the lesion, your child's dermatologist will first numb the area with local anesthesia. The entire lesion will then be cut away with a laser or scalpel. Depending on the size of the lesion, the dermatologist may be able to suitably reconstruct the area after removing the lesion. For large lesions, the help of a cosmetic surgeon may be required. Your dermatologist will let you know if additional surgeries will be required after examining your child's lesion.
If you think your child has nevus sebaceous, take them to a dermatologist.
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