John R. Tkach, M.D.
300 North Willson, Suite 203B
Bozeman, MT 59715
(406) 587-5442

Seborrheic Keratoses

Patient Information Sheet

Seborrheic keratoses are brown, scaly, pasted-on, warty-looking areas that occur mostly on the face, neck, and trunk. Sometimes the thick outer layer of dead skin will peel off or crumble off. Although they may look bad, they are not generally considered to be precancerous. That is, they are not cancers, and they do not turn into cancer. It is possible for a cancer to be hidden within a seborrheic keratosis, but that is rare. Without treatment they tend to grow larger slowly. Seborrheic keratoses can mimic melanoma, and melanoma can mimic seborrheic keratoses.

By the way, the term seborrheic here is a misnomer. That implies sebaceous oil glands. But the name has stuck for over a hundred years, and all dermatologists use it. What these are is localized areas where a well defined-portion of the epidermis is growing 8-10 times thicker than it should be. It is an inherited condition. If you check around in the family, you will find others with them.

Your treatment choices are:

  1. Do Nothing. This is not necessarily a bad choice for the short term. But with time, seborrheic keratoses grow larger. Eventually, you will want to have them treated. The longer you wait, the larger seborrheic keratoses grow and the harder they are to treat.
  2. Freezing with Liquid Nitrogen. I feel this is the ideal way to treat seborrheic keratoses. If freezing seborrheic keratoses a few times does not work, we can always cut them out later. I often treat as many as 50 seborrheic keratoses a day this way. Compared to cutting, the freezing treatment costs much less, and it usually does not leave a scar. It can scar, but usually it does not. Liquid nitrogen does sting a lot for a few seconds.
    We freeze seborrheic keratoses now, so that you are not getting cut on a few years from now. I had one lady who had 7 stubborn seborrheic keratoses on her scalp that would not go away with freezing. I cut them out, and they were basal cell cancers. If freezing does not get rid of a seborrheic keratosis, let's think about cutting it out. Sometimes freezing just does not work, and they need to be excised even though they are not cancerous.
  3. Have Them Cut Off. This is the opposite extreme. I am a little conservative about cutting on people. Most of the time, it is not really necessary to cut seborrheic keratoses off. About ten or twelve times a year, lesions I have referred for excision thinking they were cancers, turned out to be seborrheic keratoses. That's much nicer than being told you had cancer. Cutting seborrheic keratoses off is not a bad thing to do, but if you can avoid cutting, it is more convenient and cheaper for you.

So Why Have Them Treated at All?

Good question. If left untreated, seborrheic keratoses tend to get larger. Sometimes they will become very irritated and mimic skin cancer. Then the doctor may look at the seborrheic keratosis and feel obliged to cut it off. It's just a lot cheaper and easier if we freeze seborrheic keratoses off while they are small and easy to treat.

You will likely get more seborrheic keratoses in the future. I suggest coming in about once a year to have them treated. Although, you are always welcome to come back earlier to have them treated. Just call my secretary to make an appointment.

Many insurance companies and Medicare exclude treatment of seborrheic keratoses. They will not reimburse you for treatment unless the seborrheic keratosis is an "irritated" variant. They say it is a "cosmetic" concern and not real disease. This policy is penny wise and pound-foolish.

The situation is more serious than Medicare appreciates. A 2017 article by Chen et al at the Washington University in St. Louis identified that not only can seborrheic keratoses mimic skin cancers, but also standard skin cancers such as superficial squamous cell cancer, invasive squamous cell cancer, basal cell cancer, and melanoma can masquerade as seborrheic keratoses and escape early detection and treatment. Scarey, scarey, scarey. Cancer is smarter than doctors. It helps sometimes to look at the lesion with the hand-held epiluminescence microscope, but even that can fail. Freezing with liquid nitrogen usually does get rid of the seborrheic keratosis. If that does not work in a month, we should re-examine the seborrheic keratosis. When you work with me, we want to get results.

Most of time coming to see me for a seborrheic keratosis buys you some peace of mind.

The information provided in these patient information sheets is offered for general informational and educational purposes only; it is not offered as and does not constitute medical advice. In no way are any of the materials presented meant to be a substitute for professional medical care or attention by a qualified practitioner, nor should they be construed as such.

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