Section: CME Category: Dermatology

Nevus vs Melanoma

Steve McClain, MD

Steve McClain, MD helps you better differentiate a nevus from a melanoma. Dr McClain presents numerous slides of lesions and discusses how to determine whether it is a nevus or melanoma. He reviews the criteria for diagnosis of melanoma and discusses when a biopsy should be performed.

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Goals and Objectives
  1. Describe the ABCDE criteria for clinical diagnosis
  2. Define when to biopsy and what to biopsy
  3. Understanding the collaboration between podiatrist and dermatopatholigist
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  • CPME (Credits: 0.75)

    PRESENT e-Learning Systems is approved by the Council on Podiatric Medical Education as a provider of continuing education in podiatric medicine. PRESENT e-Learning Systems has approved this activity for a maximum of 0.75 continuing education contact hours

    Release Date: 03/16/2018 Expiration Date: 12/31/2020

  • Author
  • Steve McClain, MD

    Adjunct Professor Dermatology and Emergency Medicine
    Stony Brook, LI

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    Steve McClain ,MD is the owner of McClain Laboratories.

  • Lecture Transcript
  • Male Speaker: Here is Dr. Steve McClain who is actually a specialist in dermatopathology. He actually practices dermatopathology privately in Smithtown, New York. He’s founding McClain Laboratories. He trained at the University of Vermont with fellowship in dermatopathology at the university. And today, Dr. McClain is going to share with us the understanding the difference between nevus and malignant melanoma, an extremely important topic in today’s world. And certainly, in medical legal implications, you may be the first one to see and diagnose or differentiate between these two. So please pay particular attention and please welcome Dr. McClain.


    Steve McClain: That’s all I get? That was pretty weak.


    Steve McClain: I am really disappointed in that. Let’s see, we got the first. I cannot see this. Are you filming me? I can’t even see my own slides. Let me try this again. Okay. There’s no conflicts. I do own my own laboratory. I also practices at the university. I believe we hold ourselves to a higher standard, the Hippocratic Oath. If you would, I’d like you all to stand up because this is important. This is the beginning of medicine when physicians banded together and all took an oath. So here it is. I swear by Apollo the physician, and Asclepius, and Hygieia and Panacea and all the gods and goddesses as my witnesses, that according to my ability and judgment, I will keep this Oath and contract. Wasn’t just a simple get up there, how do you do? I will hold him who taught me this art equally dear to me as my parents, and to look upon his offspring as equal to my own siblings, to teach them this art, if they wish to learn it without fee or contract. We’ll come back to that in a second. I will impart my knowledge of the art to my sons, and the sons of my teachers, and to students bound to this contract and having sworn this Oath to the law of medicine, but to no one else. You may be seated. This is our information. We share it. Somewhere in there, the medical schools decided to start charging fees in contracts and stuff, but the original intent was that this is for physicians. There’s much more in there, if you want to go back to the original Hippocratic Oath, no splitting of fees, for example. They frowned upon abortions and the like. It’s all in there. The objectives, we’re going to review the A, B, C, D, E criteria for clinical diagnosis. I’m only going to show, I think, one, maybe two histology slides. In dermatopathology, you train in dermatology and pathology. We saw patients did biopsies and the like. You need to know when to biopsy, what to biopsy and you need to know how to work the lab. The references, you can find A, B, C criteria all over the place. I will point out this paper by Skope [Phonetic] et al, McClain’s name is on the end of that, using the dermatoscope in the laboratory. The dermatoscope is one of the tools I’m going to talk about today. I am from the Show Me State, the Green Mountain State and now the Empire State. I trained in dermatopathology at NYU. Absolutely one of the best places to be. That was an intense experience. In 1994, I went to SUNY at Stony Brook and became the director of dermatopathology there. And I’ve been doing wound healing research as well as aside. Started my own lab about 10 years ago. And we’re focused on making a diagnosis with photographic proof. And the way this works is something like this. There’s two aspects of this. There’s the dermato and there’s the pathology part. And it’s important when podiatrist practice like dermatologist that they make a clinical diagnosis. Your clinical description, your clinical diagnosis is crucially important to the pathologist. I urge you, when you see the patient, you see something that’s abnormal, write down your diagnosis. Make a diagnosis, okay. And there are several ways of getting to that point. Number one, there’s the head and there’s the heart. By head, I mean, there’s the published criteria, the criteria that you can use. But there’s another side to decision making and that’s the part that your experience teaches you and that’s your heart or your gut, your gut instincts.


    What about that lesion? And the lesion here is depicted in blue. And a biopsy is going to be made approximately in the black ring there. Okay. But clinically, the ABCs are pretty simple to understand. A is for asymmetry. You can’t fold the lesions over in either direction. Border irregularities like the Coast of Maine. Okay. Nevi have relatively smooth borders, by and large, 90% of them. Okay. C is for color especially multiple colors or variegation, as seen in the bottom one where D is for diameter. That’s the published one from the American Melanoma Foundation. I think it is on the toe. If it’s bigger than 4 millimeters, you better be paying attention to it. If it’s on the toe and it looks brown and it looks like a pyogenic granulomas growing in the middle of it, I’d pay attention to that too, those are bad signs. Okay. So you decide to do a biopsy and you’ve done your biopsy and you’re going to send it to the lab and you’re going to send it to whichever lab you want. But, I prefer you send it to a dermatopathologist because we’re trained in skin pathology. That’s the reason for being for many of dermatopathologists is to not miss melanoma. That tiny little circle below the line is what it looks like when it comes in the lab. It shrinks up. It looks pretty small. And the pathologist comes in and puts head and heart and looks at that gross specimen and begins to slice it if it’s big enough, or we put it in the lab and we make slices with the slides. So we do thin slicing. How many of you have read Malcolm Gladwell’s book, Blink? Anyone? No. Excellent book on decision making, talks about head and heart. Pathologists do the same thing. Okay. But your clinical description in diagnosis make a diagnosis of your own. Okay. If you consult someone else and you haven’t made up your mind, you’ll follow them. You must make up your own mind. Right or wrong, make up your own mind. Okay. Here’s another example. The specimen comes into lab. And this is what, for example, of what my reports look like. There’s a gross picture and how we sliced it. This is melanoma as you can see. Specific type, desmoplastic melanoma, and these are the special stains and we put them together. Okay. That’s the kind of reports we do. And we can say upfront the margins are involved. It’s important to get that information right upfront. Well, these don’t come in with their names on them. How many wants to guess which one is nevus and which one is melanoma? This is the pretest, so study them for about 15 seconds. Make up your mind, A, B, C, D. Make up your minds right now. Write it down. I want you to write it down, nevus or melanoma, A, nevus or melanoma, B, C, D. Okay. I don’t see anybody writing. Okay. It’s important that you write your answer down and that’s why I was pestering you about it. The pathologist’s dilemma is that these don’t come in with the names attached to them and they don’t come in to your offices, nevus or melanoma. Maybe history of melanoma. I pay attention to history of melanoma because there’s about 8% chance that they’re going to develop a second melanoma over the course of their lifetime. Or a family member may. But most of these come in with no names. It’s up to the pathologist to decide. Is it nevus? It is melanoma? And that’s what I try and get to. And then there’s a third category called, I don’t know. And it’s okay to say you don’t know. Okay. Or it’s possibly that there’s a nevus with a melanoma. The two are combined. That happens about 20% of the time, 20% of melanomas arise in conjunction with the nevus, mostly congenital. Okay. So we put the clinical with the pathology. There’s a small biopsy, believe it or not, that’s melanoma on the left foot. Okay. This was from a dermatologist. DN up here at the top, DN is dysplastic nevus versus in a history of melanoma. And this is their second melanoma. Melanomas tend to be poorly circumscribed. We only have a partial biopsy. We really don’t know how big this thing is. And sometimes the pathologist gets misled with a small biopsy thinking the lesion is small. Okay. If you tell them it’s a 10-millimeter lesion, that helps. Any information you can give to pathologist is useful.


    Okay. Not all nevi are exactly just simple small round oval things. These are called nevi. These are called bathing trunk nevi. These are in children who have Touraine syndrome. I’ll come around and point. Notice that some of these small spots, for example, multiple small spots. I’ll show you another example. Those are characteristic in congenital nevi. And these are pretty variable. These patients have a hamartomatous growth of melanocytes. The melanocytes migrate out from the neural crest during embryologic development. Then, these lesions can be pretty complicated, they can have eye findings, heart findings and it can involve the brain. And this is called Touraine syndrome or neurocristic hamartoma. These are bad things to have. The risk for melanoma in developing this is about 30%. And the bigger the lesion, the more likely they are to develop melanoma. Okay, these are kind of sad. Here’s another agminated nevus, agminated means grouped, clustered. Clustered nevus, when you see this pattern, this is called the nevus spilus. And the word is agminated, that’s the term for it. Again, each one of these is part of an individual congenital nevus. Each one of these looked a lot a like. Okay. Here’s a congenital hairy nevus even smaller. Same basic pattern under the microscope, but small and hair is growing out of it. Okay. Those are examples of congenital nevi. Most nevi are congenital, I’ve come to believe. It used to be said that about 80% were acquired and 20% congenital and I think it’s probably more likely the other way around. That they’re mostly congenital. Okay, next. Congenital hairy nevus. Okay. Where do biopsies important? Sometimes you want to biopsy the thickest area and the thickest area in this particular lesion, part of which you might guess I’m covering up. The thickest area is on the right. What do you think about that small area on the right, nevus or melanoma? That [indecipherable] [12:21] is a nevus. And if you biopsy the wrong area, you could miss the melanoma. Okay. When in doubt, take a larger biopsy, if you’re using a punch, use several. Okay. But if you biopsy that one on the right and thinking you’re getting the thickest area, you may will be but it’s actually the nevus and you could miss the melanoma on the left. Okay, melanoma and arising in a nevus. About 20% of melanomas arise in conjunction with a nevus. And it’s often a small congenital one like those on the right. And the patient will tell you, “I’ve had this lesion my whole life.” Yeah, the one on the right. The one on the left is the new melanoma that’s been growing for 10 years or 20 years. Okay. Indications for biopsy, we should all know what our threshold is, when we’re going to do the biopsy. Indication A, patient comes to you and says they want a biopsy. Well, if you don’t give them the biopsy, where are they going to go? Down the street to a better podiatrist, right? The last doctor they see is the better doctor, hate to tell you. For patients already been to another doctor and told you they want a biopsy, then you better you do it. Some of these, we haven’t seen too ugly yet but always biopsy ugly. If you think it could be cancer if it’s ulcerated, you should always biopsy those or send them to someone who’s going to do the complete excision. But you must ensure that a biopsy is made because that’s the first step. You must make a diagnosis and get a biopsy, or get them in the hands of somebody who will do a biopsy. If it’s recurrent, partly removed before but now it’s regrowing or any other kind of treatment failures frankly, the reason for doing a biopsy is sometimes you need biopsy proof. They need to be entered into a study, whatever. Or you just need the proof. You need the power to send them on to do the excision or to do the sentinel node biopsy, if it’s a melanoma case. This is my favorite 007, newly graduated, residents coming out, wants to know, what is it, how do you find out for sure what it is, you biopsy it. Okay. And the reason for that is early diagnosis saves life. We know that, but unless you take the step of making the diagnosis, making the biopsy, they don’t get in to the system to get treated, the patients don’t.


    What do you think about this one? Nevus or melanoma. That’s about a 3 or 4-millimeter pigmented lesion is the way it looks. That’s melanoma on the foot, a partial biopsy. Okay. Even a piece is better than none. I might miss it on a small piece, but then the ball is in my court, it’s my failure to diagnose, not yours. So you share the liability when you bring a pathologist onto your team. Okay. What’s this? African-American patient with a completely pigmented nail. And what about that proximal part right there, what’s that called? I can’t hear you. Hutchinson’s sign, right? Hutchinson was an English surgeon and he described, the melanocytes migrate in melanoma and they migrate right up out of the nail matrix and onto the proximal nail fold. This is Bob Marley’s toe. Okay. By the time he was diagnosed that it ulcerated, and they were going to amputate his toe appropriately enough, and he chose not to. The diagnosis of the pigmented streaks and if they’re broad, single, growing, all important signs but that Hutchinson’s sign, you better be looking for it. Okay. Evolution, I said evolution is important. This is the later picture. So you want to know how this thing got to look this way. It started out looking like this. Now, if you knew it looked like this and ended up like this, you’d say, “Wow”. But most of us don’t take pictures as we go. But if you’re concerned and you decide, “I’m not going to biopsy”, I think it’s wise to take a picture of it. And that’s what the dermatologists do. Okay. They often take using these as a dermatoscope. These are great tools. The dermatologists love these. I’ve been using one for about 20 years now ever since I left NYU. I think they’re phenomenal tools. The ophthalmologists who look at melanoma on the eyelids, they use a slit lamp. Very similar. Magnified, evenly illuminated, often times cross polarized. They’re not that expensive to my way of thinking. They’re somewhere between 200 and $1200 depending on what you buy and how much. Here, you can get a little attachment for your phones. Now, we can be absolutely sure that that picture did not come from that young woman’s shoulder. I’m pretty sure it’s a young woman’s shoulder, because that’s sun-damaged skin in that little picture on my computer. But we study evolution with photography overtime. That’s some of the models I used in the lab. I published that paper, I think, here. Published this paper on ex vivo dermoscopy. Now, this is a goofy paper. So you guys can relax on this one. But, what we did was we pulled the specimens out of formalin and did the dermoscopy ex vivo in the lab. And many of these pictures that I’ve shown you have come from there. I’ll show you many more. This one, for example, in early days, I was kind of yellow with my background. I think I’ve gotten smarter. What do you think about this one? Nevus or melanoma, or I don’t know, anyone? This one’s not so easy. This is melanoma and that white zone in the center is a scar, that’s where the prior biopsy was. And that’s what led to this excision. Okay. So the ABC criteria, again, is symmetry, the borders like the Coast of Maine. If you see three or more colors in a pigmented lesion, you better get a biopsy. There’s bonuses. Any blues, any grays, any whites in the middle of it, pay attention. Those are signs of regression. I think anything over about 4 millimeters. In New York, maybe I’m just more sensitive or maybe it’s just all the malpractice attorneys who live around me, but I found melanomas as small as 2 millimeters. Okay. This is just a cutoff. If it looks ugly and it’s 2 millimeters, get it off. You know why? If a patient’s worried about it, and you say, “Let’s watch it for a month.” Well then that puts the ball in your court, you must watch that patient. If you fail to follow that patient, it becomes a problem. Okay. What do we mean by evolution if it increases in size, increases in pigment, decreases pigment, regresses, if it moves around. Okay. That’s what evolution means. Nevi tend to grow in a pace with the size of the skin. As you get older, you have more skin, your nevi get a little bit get a little bit larger.


    Okay. Now, we’re going to do some quick ones. Nevus or melanoma? Melanoma. Okay. Or you can say ugly. It doesn’t matter. Okay. If your gestalt says it’s ugly, that’s your experience telling you, I don’t like that. If you wouldn’t like that on your mother’s face or your child’s face, you should get it off. Okay. Melanoma with regression. Where is the melanoma here do you think? Is it here, here or here? I didn’t hear you. Somebody haul her out. Actually no, this is a solar lentigo, this is the edge of melanoma, edge of melanoma and here’s a scar. This is a re-excision, so it’s kind of tricky. Notice how modeled the skin looks. If they’re old, if they did a job out in the outdoors, if they were a golfer or especially Irish golfers on Long Island, they’re pretty numerous, if they have really bad sun-damaged skin, heliosis, pay attention. If it looks weird on sun-damaged skin, pay attention. Persistent melanoma adjacent to the scar, so, most of this was shaved off and there were just those two little foci. Sometimes the re-excision is harder to go back, you can’t find the lesion sometimes. Nevus or melanoma, note, there’s a white color, there’s some blue up here. There’s dark crown. There’s at least three colors in there. Look at the borders. Now, the reason we’re able to make these diagnoses is that someone took off most of the lesion. I have the whole lesion to study. The chances of me making an error on those are almost zero. But if I get smaller and smaller biopsies, I can’t often tell. Okay. This is one of my favorite, this is a zone of regression right down on the middle here, irregular borders, multiple colors. But again, we have the whole lesion. If it looks ugly, if your gestalt says, “Yuck, that’s bad”, you don’t tell the patient that’s bad. You say, “I think this needs a biopsy.” Don’t tell them they need a biopsy, that needs a biopsy. Okay. You have to convince them sometimes. Or sometimes you have to make them sign out and say, “I don’t want a biopsy.” You make them sign a piece of paper that they refused the biopsy. Okay. That protects you a little bit. I know that sounds like defensive medicine but that’s what you have to do sometimes because patients don’t necessarily want a biopsy. This is the smallest one. This is about 3.5, 4 millimeters or so. This is melanoma also. There’s a little white spot, I think, right here. Hard to tell. This nevus is larger than the melanoma. Melanoma, nevus. Okay. Now, how do I know? Because we studied it on microscope. If you don’t know, you biopsy it. It’s very simple kind of rules. Okay. Next, what do you think? Beauty mark or an ugly mark? Well, it’s ugly enough to get biopsy, right? Someone thought it was ugly. So then that you’re correct but it happens to be a nevus. The nevi tend to hang together in an organized way. If you see order, that’s generally a nevus. If you see disorder, that’s generally melanoma growing ever which way. And if you order plus disorder in the same lesion, it may be melanoma rising in a nevus. Is this orderly or disorderly? There’s a certain amount of order to it. This is a congenital nevus, in fact. And the margins are, you know, it’s maybe out by half a millimeter or so. And patient doesn’t need a re-excision. Congenital nevus. Okay. We would like to think nevus or melanoma is usually pretty easy, this one is a nevus, by the way. It’s small, the ruler in there, those are millimeters across the top. Nevus. Okay. Now, some lesion on the foot. This is on volar skin. You can see the glyphs, right? And where is the pigment lying? Little hard to tell in that picture. Look at this one, where is the pigment lying? On the surface, where the eccrine ducts are emptying, on the glyphs, or in the grooves? It’s in the grooves, right? Very distinctive pattern, it’s small and it’s in the grooves. That’s the pattern of a nevus on volar skin. Okay. I was trying to go back.


    By dermoscopy, you’ll see the same groove kind of pattern which you can see down into rather than there’s reflection from the volar skin. The cornified layer in the volar skin is a little tough, but there they are. Here, the melanocytes, these are nested. If you wanted a description of nevus under the microscope, you would say that it’s mostly nested and most of the nests are at the dermal or epidermal junction. As you’ve heard, no doubt, in other lectures that nevi on volar skin have more cytologic atypia. There’s more weirdness is in the nevi on volar skin. I hate to tell you but its affect the line. Nevus or melanoma? Looks pretty bad. This is a halo nevus. It’s a nevus undergoing regression. Okay. And one of the things you see by dermoscopy or this little cookie bite areas, where it looks like the cookie masters bitten out a little piece of the nevus. And sometimes you’ll see a whole bunch of bites all around the edge. This is one of the clues to halo nevus by the dermatoscope. Okay. Which one is nevus? Which one is melanoma? Pretty hard, isn’t it? Which ones should you biopsy? Both of them, right? The old joke goes, the surgeon, the internist, the psychiatrist and the pathologist went out hunting and so the internist says, “It looks like a duck, quacks like a duck. I wonder what else it could be.” And the psychiatrist says, “Looks like a duck, quacks like a duck. I wonder what he is thinking.” And the surgeon comes in, “Looks like a duck, quacks like a duck, blam, blam, blam, blam.” Let the pathologist figure it out. If you don’t know what else to do, take a biopsy, send it to your favorite lab, and you’ll know this one’s the melanoma, and the one on the right is the congenital nevus. Okay. I’ll be around at the booths, so you can come by and talk with me. I have 13 seconds left for your quiz. Which one is your melanoma? Shout them out. A and D, perfect score, you win. I’m done.