Moles (Nevus- singular, Nevi-plural) and Melanoma
Patient Information Sheet
What Are Moles?
Moles are small collections of nerve-like cells some of which make melanin pigment giving them a brown color. Some moles lack pigment and are flesh colored instead of being brown. The reason we dermatologists are concerned about moles is that sometimes they turn into a cancer called melanoma.
Sometimes people come to me expecting me to freeze off moles instead of cutting them off. Freezing does not hurt moles, but it won't remove them. Freezing will remove growths in the epidermis, but not below that. Moles, on the other hand, are collections of nerve-like cells below the epidermis. To remove moles, it is necessary to cut them out.
When we are being formed as babies inside our mothers at about age 2 weeks of embryonic development, a tubular structure down the backbone called the notochord develops. Two ridges of cells arise, one along each side of the notochord. These neural crest cells migrate as a sheet, one on each side of the notochord from the back of the embryo all the way around to the front to make the skin. That's where the skin comes from. These two halves fuse in the midline and complete the formation of the skin as an envelope around the fetus. We don't usually notice this fusion line. That's what that little notch is in the middle of your upper lip.
As the precursor skin cells migrate, they accidentally tug along some of the nerve cells. These misplaced precursor nerve cells don't belong loose in the skin. Usually, when babies are born, they don't have any moles. As time goes along, these misplaced precursor nerve cells grow into a clump of cells. That is what a mole is. On the average, most people have about 27-30 moles. Some have only a few moles and some have hundreds. As we grow up, we get more moles. It is normal to get more moles, for then to grow out like a bump, and to get darker.
It is not necessary to remove all moles. Removing a mole means trading a mole for a scar. It is worth it if the mole looks or acts suspicious. But, it may not be a good trade if the mole does not look suspicious or act suspiciously.
The reason we are concerned about moles is that some old moles turn into a serious form a skin cancer called melanoma. Sometimes new moles are melanoma. There are two factors in the development of melanoma: 1. Inheritance and 2. Sun exposure. If someone in your family has had a melanoma, your statistical risk of getting as melanoma becomes 10 times greater. Sun exposure (ultraviolet light A and B) is the major cause of melanoma. You cannot select your parents, but you can choose to use a sunscreen.
As of 1996, the worldwide risk of developing a melanoma was estimated to be 6.2 women per 100,000 women per year and 4.5 men per 100,000 men per year. This represents a big increase as compared to 50 years ago. The lifetime risks of melanoma have increased alarmingly.
|Date of estimate||Lifetime Risk|
|1975||1 in 1,000|
|1986||1 in 250|
|1995||1 in 78|
|2005||1 in 59|
Early recognition and treatment of melanoma are very important. They represent our best chance of curing melanoma. Melanoma is a peculiar cancer very different from other cancers. Sometimes people develop metastases (distant spreading) in spite of early and complete excision of the original melanoma. One explanation of this unfortunate event is that the melanoma had spread (metastasized) before the patient even saw the doctor.
The early recognition of melanoma and suspicious moles is one of the most difficult tasks facing dermatologists and their patients. The best way to know if a mole is cancerous is to cut it out, process the tissue at the hospital laboratory, and have it examined under the microscope by a pathologist. But, even then, it may be difficult to recognize a melanoma on microscopic exam. So far, we lack a clear-cut biopsy stain that will tell us unequivocally if the mole is a cancer. There are new immunohistochemical stains that are helpful but not foolproof.
Epiluminescence microscopy is a method of examining moles with a hand held microscope. This method sometimes improves the accuracy of clinical diagnosis by about 10-15%. It does not hurt. Also called dermoscopy, I use this daily.
My intention is to listen to you. If you have a mole that looks normal to me, but worries you, we should talk about doing a biopsy on it. Sometimes people have an accurate inner sense about these things. Detecting cancerous moles early is a team effort. Let's work together- you, your spouse if you have one, and Dr. Tkach.
Warning Signs in Moles:
If you have a mole that develops one of these warning signs, you should have a doctor examine the mole. Normal moles are symmetrical, have a sharp smooth border, uniform color, and do not itch or bleed.
- Asymmetry: Draw a line down the middle of the mole. Do both sides look the same?
- Irregular Border: Normal moles have a sharp, clear-cut outer margin (border). Melanomas may have little finger-like projections of cancer cells migrating outward or the border is fuzzy and not clear cut. These borders are irregular.
- Color: Normal moles tend to have a uniform color. The more variety of colors a mole has, the more suspicious it is. Most normal moles are brown. Suspicious colors are very black, white areas, and red.
- Change of Color: A mole is suspicious if it changes color.
- Sudden Growth or Sudden Appearance of a New Mole: Sudden appearance of a new mole where no mole previously existed. Two thirds of melanomas appear as new moles.
- Surface Changes: Development of scale or small bumps on the surface of a mole.
- Incontinence of Pigment: Leaking of pigment or color from the outer margin of the mole into the surrounding skin. This fits in with an irregular border. Sound peculiar, hard to understand? If you see this on one of your own moles or someone else's, get it checked.
- Progression: A mole may not look bad, but it keeps growing.
Very Suspicious Signs:
- Bleeding- other than from injuries like getting scratched.
- Ulceration- development of a hole in the skin.
- Inflammation- turning red and swollen.
- Sudden, rapid growth.
The prognosis in melanoma depends on the thickness of the melanoma. If we catch it early, simple excision has a 95% to 99% 5 year survival.
Some Reassuring Thoughts:
My intention in letting you know about moles is not to terrorize you. The risk that any one particular mole will turn into a melanoma over your lifetime is small, perhaps 1 in 10,000 to 1 in 100,000. Often things that look like moles with some of these changes turn out to be innocent. For example, I freeze about 100 seborrheic keratoses a day. Seborrheic keratoses are innocent thickenings of the epidermis, the outer layer of the skin. They look like a cross between a mole and a wart. They occur as we grow older. They are inherited.
Melanoma in Children:
The risk of a mole in a child turning into melanoma is one in a million. That is reassuring. But it is possible for a child to get a melanoma. A mole that is not cancer but can look like cancer is the Spitz nevus. We need to be careful. We do not want a child having extensive surgery that is not really necessary. We don't want to miss a melanoma in a child.
We don't know for sure, but we suspect that about 65% of melanomas can be prevented by using a good sunscreen such as SPF (sun protection factor) 85-100. A pleasant sunscreen is Neutrogena Ultra Sheer Dry Touch SPF 100.
Atypical Mole Syndrome:
This is one of the most confusing and uncertain developments I have seen in my professional lifetime. Sometimes this is call "dysplastic nevus syndrome" or "B-K mole syndrome."
The notion is still as confused as it was in 1976. The problem is that no one can agree on the criteria for using this term. A very intense conference of extremely knowledgeable experts from many medical specialties met in 1994. They could not come to a consensus. Their great resolution to the problem was to change the name to "atypical moles."
On one extreme, there is a notion that people with this diagnosis have a 10.7% risk of developing a melanoma over a 10-year period. On the other extreme, some experts feel these are not abnormal moles, but rather just variants on growing moles. Where do I come down on this debate? Well, I would take them seriously to the extent of getting a mole checkup once a year, but not cutting off 50 moles over your lifetime. However, you and I might want to remove 10-12 over your lifetime. Some doctors like to have patients get photos of all their moles every six months to help monitor changes.
How to Prepare for Your Visit:
Our goal on your first visit is to evaluate your moles not to cut on them. Together, you and I can discuss removing a mole if it is suspicious or if you have a wish to have a specific mole removed. I shall look at all your mole and especially the moles that concern you.
I want to be thorough, and you want me to do a good job. We can do the exam one area at a time. I am not going to ask you to do anything embarrassing. You can leave your underclothes on. In my office, you are always welcome to bring along moral support- a spouse, relative, or friend. We do the exam quickly and then you dress. I do not believe in having people sit around undressed for a long time.
Listening to You. Let's work together: If you ever feel I am missing the boat on one of your moles, just tell me. I'll re-examine it. In this office, I listen to you. Your office visit should feel comfortable and natural. You should feel that you and I are working together on your moles.
If a mole looks normal to me, but you think there is something wrong with it, it should be removed. Please speak up. Usually, moles are small and fairly easy to remove.
Rev. Feb. 2, 2010 copyright Dr. Tkach
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.