Section: CME Category: Dermatology

Common Skin Disorders of the Foot and Leg - Biopsy and Pathology

Steve McClain, MD

Steve McClain, MD will discuss how pathology and biopsy can be used to help treat and identify common skin disorders in podiatry. Dr McClain will show numerous cases and demonstrate when and why to biopsy a lesion.

CPME (Credits: 0.5)

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Goals and Objectives
  1. Understand why the phrase Biopsy more - Use lab to guide treatment
  2. Understand how normal feet are communities of microbes
  3. Discuss Delayed healing, fungi and bacteria
  4. Understand Bernie Ackerman approach to skin diseases
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  • CPME (Credits: 0.5)

    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 0.5 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: Now, it’s always a pleasure to welcome one of our key sponsors over the last couple of years. I don’t think we pay enough attention to dermatohistopathology and fungal infections and that. And these are the things I picked up from Dr. McCLain over the recent years when he’s been lecturing for us. So in this, maybe we can ask him to speak on the diagnosis and pathology of common skin diseases. Now, Dr. Steve McClain is a dermatopathologist, trained in the University of Vermont and I think it was NYU. He also runs the McClain Laboratories, a pathology laboratory that hopefully some of you and many people, podiatrists in the country use to examine your specimens. So let’s welcome Dr. Steve McCLain who will give us his insights on skin diseases.

    Steve McCLain: Thank you. I’ve been here one chair for NYU. Come one, wake up. Let’s see. I am a dermatopathologist. I would like you to biopsy more and I would like you to send it to whichever pathology lab you trust. To me, pathology is local, it’s best on local. But that’s not the only way to do it. Okay. I still have 20 minutes because they haven’t started the clock on me yet. It still reads 2000. Okay. There’s no display, there’s no conflicts at least. There’s four main points I’d like to teach today if I could. I would like you to biopsy more. I’d like you to use the lab to guide your treatment. You may now think that’s possible but I’d like to show you a few examples. Second, normal feet are loaded with microbes. I know we like to think we’re all sterile that we can clean our skin often and get it down to perfectly sterile and that’s just not true. The third point, delayed healing is a direct consequence of any microbes. I know we were taught to look for MRSA and to look for specific microbes so that we could treat those specific microbes. But it turns out, as scientists, we’ve known for a hundred years that any microbes, any microbes growing in a wound whether you call it colonization, whether you call it biofilm, any microbes growing in a wound will delay or suppress healing. I was surprised that scientists knew that a hundred years ago. But it’s not the wound infection that you’d need to find but you need to treat the whole infection, the whole growth, the whole colony. And since you’ve mentioned NYU, Bernie Ackerman was my teacher. He had a specific approach to skin diseases. And so, his algorithm went down, is it inflammatory or infectious as one group? Is it neoplastic? Is it a cyst? Is it a malformation? Is it a deposit of something like mucinous and digital mucous cyst or ganglion, or an epidermal inclusion cyst? A malformation and abnormal arrangement present since birth? I mentioned deposit and the deposit such as gout or deposit such as iron or – even an injury or as he used to say, an outside in job. So that was the classification, is it inflammatory? Is it neoplastic? Is it cyst? Is it a malformation? Is it a deposit? Or is it some kind of injury or an outside in job? Okay. Now on the foot, all those same things apply. Except, you have to ask yourselves, what’s under the fungus? There’s often a layer of fungus growing on top of the real disease down below. And you may only see the fungus on top. On the foot and the leg, there’s the issues always, is there peripheral artery disease? Is there stasis? Is there lymphedema? Each of these vessel connections are important in changing the appearance of the leg and the foot. And the physiology, if the leg is leaking, if the skin is leaking, the fungi will find their way into that fluid. Okay?


    It’s not said often enough. So, and then underneath those things, is the primary disease inflammatory? I wish you would say it after me. I wish we have a blab school like President Lincoln had when he was a kid. We’d all say, inflammatory, neoplastic, cyst, malformation, deposit or some kind of injury. Okay. A little bit about me. I did get my first microscope at ’87 and now at age 62, I think I have 37 or 38. And most of them are connected up to computer so that whatever I see in the microscope, I can take as a picture and put it in a report. I did do my pathology residency in Vermont, my NYU training. And then I went to Stony Brook and studied wound healing in addition to my clinical responsibilities. And about 12 years ago, we’ve found the McClain Labs where the notion is that we provide a diagnosis with photographic proof. Here’s one of those. This bone, you could stimulate it all at once. But it’s not going to grow because it’s loaded with fungus. This is a bone plucked out of a wound in the office. I think it’s a proximal phalanx. I’m not sure if it’s right or left just from looking at it. But inside, you’ll notice on the far right, there are gram-positive grains on the top. Below that, PIS-positive grains. The two lower photos, even though it’s a gram stain, you can still see that they’re fungal. And there’s filament as organisms. And this was an eye opener for me. This was an index case. I had not seen this before. And I began to explore what is responsible, why? And the closest disease I could find was actually mycetoma or the fungal disease of India. Except it occurs on Long Island today. Okay. I don’t know why I have two objective slides in here. But there are three free references I’d like to point out to you that’s important. One is the notion of, and this is a bit of a controversy “Antiseptics on Wounds” by Robert Kirsner. You can go to Medscape and find this one. Fumal wrote one of the best papers I know of on the beneficial toxicity of antimicrobials or antiseptics. I know that’s a bad word and podiatrist oftentimes get a bit of a problem from the nurses who don’t want you to use antiseptics in wounds. But there is a real literature in wound healing, on use of povidone iodine especially. Read this paper by Fumal. Anybody has trouble finding it, send me an e-mail, and I’ll send it to you. And the last paper is by Keisha Findley, the diversity of microbes that are on the feet. Well here is Keisha Findley’s paper, it’s published in Nature, it’s almost three years ago. And a bit of an explanation on the left side, that’s the fungal access. Okay. On the left side, is the fungal access, and that’s the one TS1 DNA fraction. And on the horizontal access, going I guess from my right to my left or whatever direction, hypothenar palm, volar forearm and antecubital fossa, that’s the bacterial access. So there’s way more bacteria surprisingly on the hands and forearms than on the feet. Now this is diversity, this is numbers of different types of organisms, not a total number, not ten to 5th or whatever. Or as at lower cluster right above the 20 there, that’s all the other sites. And those, the core sites or inguinal crease, the ear canal, the manubrium, retroauricular crease, back, glabella, occiput and nares. Okay? So, the surprising part on this data, on this data is that the plantar heel had many more different types of fungi than did the toe web. The heel is a richer, more diverse environment than the toe web than on the toenail. And all of them had more different types of fungi than any other place on the body. The same thing is true for the bacteria. If you separate it out into different types of bacteria, these are all different types of bacteria on different sites. The foot is the most diverse of all the sites that they tested, and they tested 14 sites. What that means is, in order to develop a fungal infection.


    All you really have to do is add water to the skin of the foot. Just add a little water and don’t suppress it. Okay? Don’t put on the antifungals, don’t change the socks, don’t keep the feet dry and you will have a fungal infection. I think it’s been proven again and again. Inversely every war this country and any country has fought. Okay. So tinea, tinea pedis, there’s also onychomycosis. And the classic thought of the dermatologist is two feet and one hand. Right, if you’re right handed, you tend to find it on the right hand and both feet. Okay? Now, this is a little bit of anatomy, volar skin. And this is in nevus, I’ve sliced through a nevus and just put the lens right on to the nevus and you can – the brown pigment is the native pigment on the skin. Okay? This is melanoma. Now, this is taken through a dermatoscope and I don’t think we have any dermatoscope vendors here. Some of you will be using dermatoscope. Since soon, they will be teaching it in the colleges. Okay? And there’s a way to deal with a new type of image when you see a new type of lens. And this is my experience. I began doing this eight years ago and I had to learn how to deal with, how do I deal with all these different types of images? And so the simple controllable approach to dermoscopy or dermatoscopy is just this, when we go back. That’s the picture of a nevus. It’s symmetrical. It tapers off at the edges, relatively evenly pigmented. This is from the side. This is from the top down, different case. And this is what I call ugly. By ugly, I mean to say it’s symmetric, has irregular borders, has more than one color. Okay? But if you perceive it as ugly, that’s good enough because we’re highly trained. We can tell when something isn’t right. You do not want this on Aunt Millie’s face nor her back, nor the back of her hand, nor the top of her foot. It’s ugly. It needs a biopsy. So, always biopsy ugly because there’s a rule, if there’s one thing you can remember from my talk today, it’s just that. Always biopsy ugly. Okay? Don’t let them out. Don’t let them out. Make them sign a paper that they refused a biopsy. Okay? Always biopsy ugly. We’re giving a workshop tomorrow. I think there’s six of them. So hopefully, you can squeeze in. We’ll be practicing some of these techniques. We’re going to talk about the indications for biopsy. An indication A is that the patient wants a biopsy. If they come to you and say they happened to say they’ve been to Dr. X. Oftentimes, they’ll say, well Dr. X never wanted to do a biopsy. That’s exactly why you need the biopsy. If the patient comes to you wanting a biopsy or feels they should have a biopsy, you should almost always biopsy those patients. Second, you biopsy to provide a diagnosis before treatment. But frankly, in the past, some of the labs have been so bad. Let’s say for toenail fungus, you get an extraordinary number of false negative biopsy results on toe fungus. I’m not exactly sure why these toenails are hard to cut, they’re hard to keep on the slides, they’re difficult to culture, et cetera. But the notion is, we want to provide diagnosis before treatment. And so you’d biopsy in order to confirm your diagnosis. Now say, we go back to that ugly one and the pathologist had said, that’s a nevus. Anybody in their right mind is not going to take that pathologist’s word for it. Why? Because in your mind, the diagnosis was melanoma. I don’t deviate off once my diagnosis is melanoma. I prefer that it’d be out completely. Okay. Some of you teach residents and the residents want to know and I know they’re pain in the ass. I was a resident myself and believe me, I was one of the biggest pain in the ass residents you’ve ever met. Some of my staff who’s known me 25 years know that that’s true and she’s laughing over here at me. But I call it the double O7 rule. If the resident wants to know, they have their license, let them find out. Or when there’s a distinctive pattern that you’ve never seen before, you say wow, that ought to have a name. Okay. Let’s give it a proper name. Do a biopsy and find out what it is. We biopsy to create knowledge. Okay. This is a fun one. This is a dermatoscope image on volar skin and you’ve heard about the grooves and you’ve heard about the lens or the elevations on the foot.


    And nevi, for whatever reason, tend to be in the grooves. It’s almost as if you’ve dropped a little bit of income there. Okay? Or is melanoma tends to be on the high spots, on the places where the eccrine ducts are. Okay. So they’re specific diseases. If you suspected neoplasm, you think it could be a cancer under there? It may have fungus growing on top. But if you think there’s a cancer underneath there, you need to get down until it bleeds. Okay? Bullous disorders, bullous disorders, you won’t get them very often, but sometimes you will. And you should be prepared to know that there’s a proper fix that you should put it in and that’s Michel’s fixative. When there’s a dermatitis, one of the most common dermatitis, and I think I’m going to move on down here, other reasons. Okay. So this is a picture of a nevus, a junctional nevus on volar skin and the pigment preferentially seems to be in the groove. And when you see that, you can be assured that it’s a benign pattern. And if they still want it off, by all means, take it off because that’s pretty "atypical". Okay. If they want it off, I tend to take it off. Why? Because they’re going to go to a better doctor to have it taken off after they leave your office. And who’s the better doctor? It’s usually the last doctor they see. Okay? I can’t help it that some people do doctor shop. But that’s a fact to the matter. So here’s the pigmented nest and we pay attention to those and these nests appear to be equidistant, relatively uniform and so it’s benign. Maceration, how many of you think that all maceration is fungal? Anyone? It is. Virtually, all maceration is fungal. It’s a consequence of having added water to the skin. And I don’t care where the water came, from the outside or whether the water comes from the wound that’s right next door. When there’s too much water present, the fungi will grow. And it will grow all around those. And it needs suppression. Okay. One could practically see that yellow chunk of fungus in there and the hi-fi because I’ve so zoomed it in, okay? Try it. If you don’t believe me, all maceration is fungal, send me a biopsy. Okay. When dermatologists examine the skin, we’re all going to cover a couple of diseases here, granuloma annulare or GA. It’s inflammatory. It’s not infectious as far as we know. It’s often annulared and has a raised, kind of beaded appearance around the periphery. And the main contrast for the pathologist is necrobiosis lipoidica diabeticorum or NLD. Okay? They’re both actually pretty similar under the microscope and that they’re both granulomatous except one occurs primarily and preferentially in diabetics, which you see quite commonly. And the other one is just it occurs randomly. Okay. All histiocytes here are red. And so the layering is a typical pattern under the microscope for necrobiosis lipoidica. And so the histiocytes here or the macrophages are staining red. Oftentimes, you will see this, this is a dermatoscopic picture. And you see how much it changes. But this telangiectasia and the yellowness are part of this disease. Okay. Again on the leg. Okay. Here’s another one and I think this will be the last disease we’ll talk about. Common diseases on the foot, which have these particular plaques, particular color, kind of reddish, kind of brownish, palms and soles. Any diseases you know on palms and soles together? Psoriasis is one. Okay? This is a little further on in the same disease and why they say that there’s fungus growing on top of everything. All that yellowish stuff is the fungi which have grown in the cornified layer on top of the real disease. Okay? So we sometimes see these things peeling off sheets. But the underlying disease is the red part. It’s also underneath the yellow part where the fungus has grown. Okay? And in the mouth. I say well McClain, we don’t want to look in the hands, and we don’t want to look in the mouth. Well, you should because sometimes the clues are there. This is syphilis. Mouth, hands and foot. Okay? It’s still out there. It’s still in our city. And the classic is they show ham-colored plaques, discreet kind of pinkish plaques. And again on the palate, soft palate.


    Okay. This is the last one, I guess. Lichen planus, exceedingly common, involves the nail, involves the scalp and the classic position is on the inside of the forearms. Because if you’re thinking about lichen planus, again, look on the forearms and look inside the cheek. What you’re looking for are flat-top papules, sometimes with a lazy white – I don’t know why they called these looked like curtains. But this is Wickham striae. Okay? The name for the lazy white pattern on the top. Okay. I think that’s about – Okay. We’ve got time for one more. Why would anybody in their right mind, they would go to a pathologist to have their wounds healed, or their psoriases taken care of? I do not know, but a friend of mine sent me this patient. He says, Steve, you’ve got to see this patient. I say why? He says, well she doesn’t have any insurance for one. And you’re the only one who will see her and I’m closing my office and I don’t know what else to do. So I said okay. She’s got rheumatoid arthritis. She’s got head to toe flakes. I still remember this lady Natalie like, it was my great aunt. And she’s flaking all over the place. And so I looked at her foot, and her toes all bent over and you can just barely see it. And you see that kind of it looks like soap bubbles on the big toe. Well that’s all the fungus growing on her big toe. But going up the leg, there were these discreet alligator scales, and I worked on these and I cleaned it off and I was able to peel off some of these things. And it came off in big sheets, like scales, big scales. This is tinea imbricata. And then this patient, it happens to be dude, a Candida. And she would never take any medicine. Once having proven what this lady had, she still refused to take any medicine. She said, oh I’ll have complications. I said Natalie, you’re living like a leper shut in your room. You won’t take any medicine. All she would put on was olive oil. So this lady is just feeding her fungus with olive oil. And every time I, finally after two months I said, I can’t see you anymore. I can’t keep making up medicine and putting stuff on you. You refused to take a simple medicine. Her liver enzymes are less than 20. Okay. Tinea imbricata in this case it’s due to candida. We have specific antibodies. We can identify candida in these things even when you think we can’t. Okay. I think that’s it. I’m not going to go into recipe for ulcer. Come by and talk with me. I’ll be happy to discuss this at any time. Thank you for your attention.