Posted tagged ‘dermatology’

Nevus sebaceous – what we don’t know about their management

June 5, 2017

The Pediatric Insider

© 2017 Roy Benaroch, MD

Trupti sent in a quick question, to which I’ve written an honest but worthless answer. Such is medicine, sometimes. But honestly is always the best policy, right?

“Hi Dr. Roy, can you please shed more light on nevus sebaceous and its management?”

Nevus sebaceous – also called “nevus sebaceous of Jadassohn” or “sebaceous nevus” – is a fairly common skin patch. And by fairly common, I’d say I see a new one of these on my patients maybe once a year. They’re usually found on the head or neck, often noted at or shortly after birth. I’ve also heard they can arise later, but I don’t think that’s too common. They look kind of waxy and bumpy, with a yellow-brown or yellow-pink color, and if they arise in the scalp they stand out a little more because they don’t grow hair.

Really, the only management decisions are whether to have the removed, and when. Do they have to be removed? The answer here is a clear and definite “maybe.”  Derm textbooks and many docs who trained in the past will tell you that many of these will turn into cancer, so they ought to be lopped off, excised, and fully extirpated with extreme prejudice. This is based on older studies that found cancer rates up to 10-30% — and, yes, if that were true I’d say get them off. But more-recent studies since the 1990s have found much lower rates of cancer, perhaps less than 1%. Those older studies had mis-classified pathology findings as basal cell carcinomas, when in retrospect they were benign. We honestly do not know exactly how many of these will develop into cancer over a child’s lifetime, though cancerous transformation certainly isn’t common when kids are young.

There still isn’t a consensus in the dermatology literature about this. Though some authors recommend prophylactic removal because of this cancer risk, others do not. Here’s a table from a 2012 review – note that newer recommendations tend to be less surgery-happy, but they’re still all over the place:

 

OK, so that’s clear now. Another reason to consider removal is cosmetic – and especially if one of these is on the face or the side of the neck, you’d probably want to consider removal for your child. That’s something to talk w/ a plastic surgeon or dermatologist about. Removal of one of these will always leave some kind of scar, and you want an honest assessment of what it will look like afterwards – there’s no such thing as a no-scar removal.

As for when to take them off, well, there’s no consensus about that either. In early childhood they’re smaller, so hypothetically easier to remove, but it’s harder to use safe local anesthesia in younger children. You could wait to see how it develops through adolescence, but if it gets much bigger a more extensive, possible multi-staged, procedure is going to be needed.

Bottom line: we don’t know if these should be taken off, or the best time to do the procedure. I know, clear as mud – aren’t you glad you asked, Trupti? You should talk with your child’s doc, and get the opinions of a few knowledgeable plastic surgeons to help make the best decision. Good luck!