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Skin cancer in a rural setting: A practical guide for diagnosis

Chantelle Vonarx: Welcome to the latest instalment of our rural health webinar series. This webinar is “Skin Cancer in a Rural Setting: A Practical Guide for Diagnosis” and it's going to be facilitated by Dr Jeremy Hudson who's the Chair of Dermatology for the RACGP, as well as a Senior Lecturer in Skin Cancer Medicine and Surgery for James Cook University, and a Clinical Director for the North Queensland Skin Centre, which is a research based clinic in Townsville. Dr Hudson has spent most of his career being a rural and remote GP before specialising in skin cancer and he also has a strong interest in medical education and improving clinical guidelines. We're very pleased he could join us this evening.
We would also like to start with an Acknowledgement of Country. RACGP would like to acknowledge the traditional custodians of the lands on which is event is being broadcast and we pay our respects to their Elders, past, present and emerging.
RACGP Rural would also like to thank our sponsor, Ochre Health and Recruitment. Established and still owned by two procedural GPs, they operated a network of medical centres around Australia, as well as operating a medical recruitment agency that works with hospitals and medical practices throughout Australia and New Zealand to source and place locum and permanent doctors across a wide range of specialties. We greatly appreciate their support of this webinar series.
And just finally before we start a few housekeeping things to cover. All participants are set on mute just to ensure that the webinar isn't disrupted by background noise, but we do encourage you all use chat function to ask questions and provide comments. And finally, the webinar has been accredited the two CPD points. In order to gain the points you just must be present for the duration of the webinar. We do also ask that you complete an evaluation activity that will pop up at the conclusion of the webinar. I'll now hand over to our facilitator for this evening, Dr Jeremy Hudson.
Dr Jeremy Hudson: Yeah, hi everyone – welcome to the lecture tonight. It's great to see so many attendees. I hope you're all well and have had a busy week like myself. This will run for about an hour and what I might do is just get started. Look if you have any questions, you can ask by voice, but you can also type in by chat. I'll try and prioritize the questions that we have the most of, and I'm very happy to stick around at the end to answer any additional questions. Right, so the focus on today's lecture is really about when you're by yourself in a remote or rural setting (and really the buck stops with you – might be hard to transfer a patient to a main city), how do you actually sample your lesions to get accurate diagnosis. Because there are a few very specific ways of doing this, and there are a few pitfalls where people get trapped up about diagnosis. In the rural setting, of course, people usually come from a distance, they have very active outdoor lifestyles, and sometimes the way that we will sample these lesions will change depending on, you know, what they have to do – if they have to go out mustering, if they've got 100 lesions that need done now because they're going to be heading back out on a nine hour drive – you get the point. And finally we'll go through some case based learning – quite a few cases we can go through, but I can cut that short if you more wanted to talk about just general questions.
And, look, I just wanted to say as well, just as the Chair of Dermatology for the RACGP, this year there will be a lot of changes and advancement in terms of how we do policies, how we get individuals involved. If anybody wants to become a member of the GP dermatology special interest group you're absolutely free to depending on how much experience you have. We want a wide range of opinions. So you can actually directly input into RACGP policy and how things are done, so do get in touch or apply if you want to.
All right, well, onto the real good stuff. So I got a quote from Blake O'Brian, my pathologist who's a very good dermatopathologist, and I'll just quickly read the quote. So I said, Blake, what do we really need to tell the people tonight? And Blake gave me this great paragraph – accurate histology is best achieved when the clinician and the pathologist have a close working relationship. You want to be able to call your pathologist when you don't understand, maybe you think they've not got the right idea about what you've been seeing – you'd be surprised how many times the diagnosis changes when you talk to your pathologist. And then, ideally, the pathologists of course gets an appropriate specimen type, they get enough tissue, they get enough relevant history as well, and in some cases images (some of these pathologists are also skilled dermoscopists). And it's very important, long term, if you tend to do a lot of skin to be really cognizant of the subjectivity and sampling error that arises in pathological assessment of specimens. So, look, what that means is, you know, pathologists can make mistakes. Pathologists do have different criteria for diagnosing melanoma versus dysplastic nevus. When you do this a lot you may actually change your management if you have a lot of in depth knowledge about how the slides are made, how the stains are made. So, look, long term, if you're planning on doing a lot of skin it’s a good idea to look at an educational guide or histology primers (and you can get these from some pathology companies or they’re free online). So good idea to educate yourself if you're doing a substantial amount.
I might just turn off my own video so it improves my bandwidth and you don’t have to look at my ugly face all night, okay.
All right, so a couple key rules here. So my two big rules I want to give you. First of all, make sure when you get a specimen you have both a normal and an abnormal skin interface – that actual interface where it changes over is one of the most diagnostically useful things because it gives a pathologist a default to compare the skin to. And, secondly, the more tissue you give the pathologist absolutely the better for the diagnosis. All right.
Now, we'll be covering this from two different aspects. First of all, we’ll be saying let's look at the actual techniques that exist – how do these techniques work, how should you be using them? So there's the old punch or trephine, shave or the saucerisation, curettage, incision or biopsy, excision, and wedge. And then, if you have a lesion that you suspect is one of these things, how should you approach it? So that’s suspected melanoma, keratinocytic cancer (that's the new term for non-melanocytic skin cancers – so basal cells and squamous cells), what about a suspected keratoacanthoma (which some people would argue is a variant of SCC), sampling cartilage, ulcers, blisters or inflammatory areas, and potential melanoma of the nail unit. Now, look, you might feel that some of this is a bit beyond your pay grade. That's okay. This is just to go as far to help as many people as possible, because often when you're working remote, you may justify doing it because you're the only one they can see.
Now, quick touch on anatomical danger zones. Look, this is just a quick list I like to type up. Especially if you're going to be biopsying or operating around the head in the neck, you need to know where these structures are. If you're not doing so much head and neck, you need to be aware of things like dorsum of the hand and, potentially, the head of the fibula for a few structures that can be damaged there. There are courses, surgical courses, through different training groups, including RACGP, you can do. There are great online articles through eMedicine – highly recommend doing these if you're going to be operating in that area. Now, you can take a photo of this if you want or have access to the slides later. The little star next to some of these means that there is an accompanying vessel that's at risk. Temporal artery is highlighted because that's the most commonly damaged – I've heard that in about 10% of people that may loop a bit more shallowly. Anaesthetics may temporarily disable the motor nerve for a day or two, sometimes hours. Look, that can be worrying sometimes, but when you get down to it, if you know your anatomy well and at what layer the nerves live, you can be pretty confident with your surgery. So it's important you know your anatomy. And this knowledge also lets you do nerve blocks with sensory nerves and claim that as an item. Generally speaking, keep the superficial fat if you want to avoid damage. Be careful in the elderly or people with no fat because they're a bit more shallow. And you can sometimes do hydrodissection, putting in a lot of anaesthetic to try and push the tissue off the nerve if that would help.
So, punch biopsy or trephine. Okay variety of sizes, these come, you know, ranging from one up to eight. Look I've never used a one in my career. The only use I see for a 2mm is to biopsy the edge of an eyelid for suspected BCC because you don't have to suture an eyelid with a 2mm biopsy. Keep in mind it's a very small piece of tissue that you're removing. Some pathologists say that if you’re biopsying it for a suspected BCC on the eyelid and it comes back as benign you may be obliged to do a second biopsy just to confirm. Three millimetre or four millimetre, a little bit of personal choice. I mainly use four millimetre. And then five to 10 millimetre, I tend to suture these. These are very good sizes if you want to remove a small pigmented spot in total or in toto. Do remember that if you're partially sampling a lesion, that's a biopsy. I know I use the term a bit loosely. If you're removing an entire lesion with a large punch and then you suture it to close it and the intent is to remove the lesion, that is an excision. So its intent based and whether you suture it.
Now, look, if you don't know how to do a punch biopsy, you stretch the skin and then you take the biopsy in a swivelling motion – be very careful, this is very sharp, it can go very deep). You can close it with a purse string or interrupted or dissolving sutures – however you want. And you'll see that the actual biopsy will relax and you'll see where the relaxed skin tension lines are when you release the skin. A little video here of me doing a punch on a toe. What I just want to demonstrate is, sorry bad angle, but in this case, because there are underlying structures I'm actually pinching the skin to raise it up off the underlying structures (that's another safety technique). And you can tell the depth often by feel if you do it enough. Whoops, it’s not playing. My apologies, I thought it worked about 10 minutes ago when I tried it, but obviously I'm a bit of a McGuffin with that, sorry. All right, we'll just skip that one, but it really is just doing a punch there.
OK, now three versus four millimetre punch – why do I prefer a four millimetre punch? Here's the mathematics of it. I showed surface area and volume. So you don't, you know, have to think too much about it, if you go from a three to a four millimetre punch you get 1.78 times the tissue. That's a lot more tissue – almost double – for just a millimetre increase in diameter.
Now to suture or not to suture? Well, look, there was one decent trial done on this. Basically they did a bunch of four and eight millimetre punch biopsies of the thighs and the arm and the back. They either closed it with surface nylene or they let it heal by secondary intent (and in that case, they would have put something like algisite on it, dressed it with a dressing, maybe put vaseline on it in the future, and given it a couple of weeks just to heal up secondary intent).
And then they showed the images to the doctors, and they asked the patients, and they said how satisfied are you with this result? At four millimetres on those areas patients and doctors found no difference in the scarring (so suture versus non suture). Now, with the eight millimetre ones, the doctors looked at the photos between suture and non suture and they said they couldn't tell the difference. The patients however who had had the biopsy said I prefer the suturing. And that's pretty interesting – so there's a bit of patient preference for the larger biopsies to be sutured. Thighs, lateral thighs, tend to scar more, so you may want to suture that. But there might be a bit of bias due to the expectation. These doctors also used nylon sutures which would cause tracking. They didn't use dissolving sutures. I think, in most cases, if you're deciding to suture or not, it really is a weigh up between patient priorities, your abilities, their expectations… If you've got younger people who are going to be busy, a lot of people don't suture these because they find them easier to manage a scabbed up wound, you can go out and work with that and with sutures people tend to worry a bit more about it and they'd have to come back to have it removed in a rural situation unless they can do it themselves.
And, of course, cosmetics, on the face, you may want to suture – this is particularly in younger people concerned about cosmetics.
Okay, no questions so far.
Shave biopsy. Look, tangential shave normally goes through the dermal epidermal junction or the shallow dermis. You can use a scalpel if you want, like a size 10, a fixed scalpel, or you can use a pathology lab provided bendy one. Partial thickness of the skin does take 1-3 weeks to heal. Keep it covered if you want it to scar less. Be pretty careful on the lower leg of vascular paths, this may take a really long time to heal. If you go very deep into the superficial fat, that may be an intent to remove a thing totally, that's called saucerization – you do get more scarring with that. You will have a pale patch afterwards, because you're removing the melanocytes.
Question – Can you punch on suspected melanoma? I’ll answer that, yeah good question, we'll get on to that when we talk about the suspected melanomas in potential later on.
So, yeah, look, this is only really for suspected shallow lesions. When I teach this, especially at the university and to registrars, I say you can shave more if you know your dermoscopy and do not shave a suspected melanoma – this has been a big rule of thumb and I think this will be the official kind of party standard. Because you don't want to segment a melanoma at the deep aspect. While the technology is improving it can still be quite deep to, you know, if you take it out, first you segment it, then have to take it out deeper, it can be very difficult to gauge the full Breslow thickness. Personally, I shave a lot, because I get a lot of remote people, I get a lot of high risk people with many funny lesions – I remove about up to 11, 13 melanomas a week. In my whole career I've never segmented a melanoma. But if you want to be careful, know about your dermoscopy, so you need to know signs of deeper lesions, and you can look this up, but of course with like deep BCCs you might be thinking of globules if it's pigmented or arborizing vessels as sure signs of nodular. In situ melanomas may have very similar features to deep melanomas but they tend to start getting features like white scar like deep pigmentation, or linear or dotted vessel patterns when they're transitioning to invasive, and then the more bizarre the vessels get the deeper they are, the more sort of structuralist stuff. So, again, you may want to shave in a rural setting but know your limitations, know your dermoscopy.
Okay. Will this video play? No it won't. Sorry guys. You could probably look this up on YouTube. One of the things I was going to show you on this was how to apply topical haemostasis. So I’ll just have to tell you to do it. So topical haemostasis is once it's bleeding because you're in the dermal layer you get these little perforating vessels that bleeds quite a bit.
Alright, so topical haemostasis, what I use myself as aluminium chloride 20%. Very old, very old technique, this has been around for I would say thousands of years in the Middle East, they used to use it, they still use it in Turkey after shaving as an alum block. You can get it as a liquid. Don't get it in the eyes. It may delay the wound healing according to literature. Aluminium chloride, look, some people rinse it afterwards to try and avoid the delay in wound healing (rinse with sterile water). What I do with aluminium chloride is I get a little sterile cotton tip swab, I dip it into my little tube of aluminium chloride, and then I rub it vigorously.
People are asking about driclor – is it driclor? Yes, it's off the market. You could probably get a pharmacist to just make it for you. It's pretty basic stuff. I think they might use a variety of this for antiperspirant action or something like that. So yeah it is off label or off market really but it works pretty well.
So what you can do is you can either put it on a bit of gauze, apply pressure for 20-30 seconds (the rule is the more concentrated it is the faster it works, less concentrated it is the slower it works). You might need to hold it for a minute on cotton to get it to stop. If you rub it into the wound with a cotton tipped swab it will stop a lot quicker. So I mean I've used 10%, some people go up higher but I don't see any necessity to this. Look, you can actually get this both in water and alcohol. There's some concern if you use it an alcohol and then you use electrocautery you can set it on fire – so get it in water. The benefit of the water as well is that you can actually increase the concentration – you can't do that with alcohol based aluminium chloride. Look, there are a bunch of other different topical haemostatic agents, like, for example, there's Monsel’s solution, that's ferric subsulfate. I don't use that because it can stain due to iron deposition. One very clever person once wrote an article saying, well we could probably get some tranexamic acid 500 milligrams, put it in 10 mls of water, sterile, you've got 5% transexamic acid – that's an off label use – it can stop bleeding. Or I find people who have platelet problems either due to medications or genetically, you can actually use 5% hydrogen peroxide. I just feel that works better for people with platelet dysfunction. And what you do is you put that on a piece of cotton, you hold it on there for 30 seconds, and you do have to rinse it off afterwards or it can impede wound healing.
Another question – is silver nitrate also good enough? No. Look, silver nitrate I'd steer away from – it's a bit too vigorous. I would say the other agents are much easier and safer to apply. I would mainly use silver nitrate if there was granulation tissue that was out of control.
Diathermy after shave? Absolutely you can always use diathermy, you just may not have access to that if you're doing home visits or out remote. But works perfectly fine yeah. Diathermy Hyfrecator I can use it on the setting from seven to 15.
And someone is saying that they've used Nivea antiperspirant for skin tags to attain haemostasis. Yep, interesting.
Okay, curettage. Now we've got the two curettes there. We have the green one – very, very, very sharp and free from the pathologist. We've got the silver one – which is sterilisable and that's blunter. Two different uses really. Now they’re good for removing very shallow lesions. Of course, because you're basically grating the thing up with the curette, you can't determine accurate margins afterwards. But you might get a report back saying, oh you've removed a BCC and we see a high risk feature like infiltrative pattern, okay, you've got to go back in and cut that out properly. Now, be careful, elderly people, may tear, may damage fragile skin. The sharp disposable ones are very good for just completely cutting down through everything, removing very dead skin, thick skin, plantar warts, removes lesions totally. I would use the silver blunt sterilisable one for removing a superficial BCC because the superficial BCC is very fragile. What you do is you work your way across it at multiple angles, you may cryotherapy it in between – I steer away from electrocautery because cryotherapy is more reproducible. Be aware, most recurrence occurs at the peripheries. If you are very careful with selecting the BCCs that you curette, avoid the head and the neck, less than a centimetre in size, no complicated features, superficial, you might get something like a 6% recurrence rate – that's good. When you remove the BCC, the silver curette will eventually reach the dermis. You will feel this as a scraping sensation, you will hear it as a crunch, crunch, crunch, kind of crar, crar, crar noise, and you'll see little pinpoint bleeding occur. That's how you know you've got down to the dermis. So that's effective depth. But, remember, recurrence occurs at peripheries – make sure you focus treatment at the peripheries.
OK, now let's talk about another one – incisional biopsy. Now, hopefully you have a bigger screen so you can see what I've drawn in MS Paint here. There's a lesion, we are going through the lesion, it's a partial sampling. If you can, incorporate normal tissue. Remember normal abnormal interface. Even better, get normal tissue at both sides. I would reserve this for large lesions where you just cannot remove the whole thing. Or for very technically difficult areas. You need to try and focus in on the most suspicious looking area, so you need to know a bit of your dermoscaopy for this, but it's a good get out of jail free card sometimes – it's much better than doing a smaller biopsy because remember the other rule that more tissue the better. Now, even if you suture this up, you're not removing the whole thing, your intent is not to remove the whole thing, so that is a biopsy, it is not an excision okay – you can't bill that as an incision.
One thing I've done when I was out bush when I had a large one like this and we couldn't remove the whole thing (because that would require a flap) is I removed half of the lesion. It seemed relatively benign but the patient still didn't like it there. I gave it a few weeks, the skin stretched back, I then did a second one and remove the remainder of it. You can do a delayed removal in some areas – that's a bit of a get out of jail free card, because some people, if they’re out mustering, they can not have a flap or a graft on their face – it just doesn't work. But look you could always refer someone into town to get a wide excision done, but just to say that's a get out of jail trick – always good to have one up your pocket.
Okay, excision. This is a very interesting, wonkyish, excision isn't it? Now, an excision is the intent to totally remove a lesion. This may be diagnostic and/or it may be curative in the case of lower risk skin cancers. A two millimetre border of normal tissue is ideal, particularly for suspected melanoma (we'll get into that later). Look, if you're dead set it's a squamous cancer or basal cell, and you know your accuracy is good, you can do an excision to remove it both as diagnosis, both as curative, and you could change your margin accordingly to that. But everyone will sometimes misdiagnose lesions, so just keep that in mind. Now, it does require suturing obviously. Yeah you'd want to suture the thing right, but this is the gold standard for histology.
And I will just quickly go through how you map this out. The reason why I did a wonky shape is because that's how I would do sinusoidal type closure, depending on the relax skin tension line. Sinusoidal designs distribute tension in multiple angles so they actually heal with a bit less scarring, they’re a bit more resistant to tearing or ripping or popping the sutures if someone's doing heavy work.
All right, another question – how to decide the margin in pigmented lesions. Okay, now, first of all, look at the lesion in this picture. There is a mix of pigmented and non pigmented lesion I've included. Be very, very careful. If you ever see a pigmented lesion you're going to remove, stop, very carefully look for pink or depigmented area that may have regressed. Same thing the other way – you see a pink lesion, wait a second and look for any pigmented lesion around the sides. Okay, so try to include both aspects of that.
Now, another question – keratinocytic cancer, what margin is preferred? If you look up, the keratinocytic cancer guidelines, 2020 I believe is the latest version, they should talk about margins. Look, really, really basic simple things, two millimetre standard for BCCs and stuff, four millimitres for more aggressive SCCs. So you can do it basic SCC with four mil, more aggressive SCC maybe six to 10 mil.
What exactly passes over to high risk? That's a very good question because there's no black and white line. It's often a mix of features and anatomical location – bit of a lecture on its own.
Alright, so, for example, this was a melanoma in situ that I removed with a shave about a week before. As you can see, someone could easily go out bush and do some work, they could sweat, that will not get infected. So the first thing you do is you map out what you think the periphery of the lesion is with a dotted line, pigmented or non-pigmented, so dotted line. Then put your dermatoscope on it and look at the dotted line where it occurs due to the legion, look for subtle features, adjust the dotted line if you need to. So you try and do the dotted line twice – you correct it after putting a dermatoscope on it – you all need dermatoscopes if you’re going to do skin and skin cancer. Then you put your margin line around it in solid. So that's 10 millimetres for a melanoma in situ (and ideally you cut to the exterior), and then you put in the lines according to the relaxed skin tension lines at the appropriate ratio. And always record the lesion size in your notes and the clinical margin to get the defect size, because you can't rely on the histology if you get audited, because your histology will shrink in formalin, and it will shrink due to skin elasticity, you need to record this for any billing. And always very, very accurately log the anatomical location – if you say it's on the right upper arm when you biopsy it and then you come back to cut it out and you say right shoulder Medicare will say that's a different location, that's a lesion that hasn't actually been proven to be a cancer, for example, so make sure you use the same language.
Okay. No further questions at the moment.
All right, wedge or pie slice. Look, I never really use this, I just include it due to completeness.
Very rarely used, you often need to suture it. It's good for lesions where you need a deep central sample and a punch might be inadequate and you can't afford to cut it out completely due to patient factors. That will give you a very accurate idea. Look, there is still that normal border of skin – remember two millimetres of normal skin to the outside, to give the pathologist something to work with.
Okay let's go on to the lesions themselves. How we doing for time? Oh, good, halfway through, okay.
So, suspected melanoma might be pigmented, might be non pigmented, might be a mix of both.
Gold standard is excise with two millimetre margins. Now, if you were dead set, and you said I am 100% sure that's a melanoma, why wouldn't you exercise it with 10 mil margins to begin with, or greater? So that's because if they need sentinel lymph node biopsy you don't want to remove the surrounding tissue that will muck up the sentinel lymph node biopsy – so that's for invasive melanomas. Look up the melanoma guidelines if you're unsure of that. And I'll actually mention a tool in a minute you can use to decide whether they should have sentinel lymph node biopsy. If it's very large, yeah, look you could do an incisional biopsy as your get out of jail free card. It's not ideal, but go through the best suspicious area. Do not, DO NOT, partially biopsy by punch, because that may diagnose melanoma something like one in four or 30% of the time. That's demonstrated by studies.
Okay question – how to choose the punch size based on the lesion size and borders. Okay, so, first of all, you need to say, are we going to want to partially biopsy this, or are we going to want to remove the entire thing? So if it's small enough you want to remove it with a normal rim of tissue, ideally two millimeters. I hope that answers your question.
Now just to say this is recently out – couple of months old. The Melanoma Institute of Australia is a good resource. They've just published this – you can access this. It's based on a study, I think, with 30,000 people. You can calculate those three things there – first primary melanoma risk, sentinel node metastasis risk, and subsequent primary melanoma risk. This should not replace common sense. Not that I think that the sentinel node metastasis risk calculator will actually disagree with anything common sense, but, for example, normally, you wait till something is more than 1.2 or more than I think now, they say, more than one mil deep before you consider sentinel lymph node biopsy, unless it has other high risk features. They don't count mitosis anymore for sentinel lymph node biopsy, but when they did this study with the Melanoma Institute, this is a good example – 34 year old female with a point eight mil superficial spreading melanoma with one mitosis – according to traditional guidelines, you would not send this person for sentinel lymph node biopsy, but this according to Australian data actually gives them a 15% chance of metastasis risk. If you look at their guidelines they say, look if the risk is less than 5% you don't refer them, if it's between five and 10 you refer them for discussion (or if you're educated discuss it yourself), if it's greater than 10% they should have a central lymph node biopsy done. Okay, so a lot of information – this is appropriate for the more advanced people who actually get referred things – this is a useful tool.
And further on from that, there's a new funded service by the Melanoma Patients Association. There's an oncology nurse called Brooke. This is a pilot trial. She will organize and discuss and liaise for your melanoma patient all sorts of things like clinical trials, education, referral. It'd be good to refer people onto Brooke so she can see how things work. I don't have any vested interest, I'm just a big fan of rural funding and information. You can ring her yourself if you want – that's the phone number that patients can ring or you can ring.
Okay, suspected keratinocytic cancer. You can excise the thing, that's accurate. If you can't excise it, a partial biopsy is appropriate – so punch biopsy – but try to go through the full thickness. The reason for this is a lot of features that make them higher risk are only apparent at the deep margin. So an infiltrative BCC may predominately have infiltration at the inferior margin – that's why you want to go full thickness – get some normal tissue in underneath that. Also lets you gauge the depth, which may indicate aggressiveness. So squamous cancers used to be more than four mils are considered high risk, now they say more than two mils – it's kind of a rising curve, they just chose a point. If you curette it, you must send it for histology to check if it's invasive or high risk features. But is it actually an amelanotic melanoma, that's a question. I have absolutely seen things where I thought was a basal cell and it ended up being an amelanotic melanoma – happens to me 2% of the time according to my data. And what will happen is, you will biopsy this thing and they'll say no BCC, no SCC, melanocytes seen, and the first thing you need to say is look at what you thought it was – should I expect melanocytes in what I thought was a BCC? No you shouldn't. Okay, brown pants time. Talk to the pathologist, but, again, nothing harmed at the end of the day – you’ll get a bigger sample, two millimetre margin, they'll do special stains, away you go, you'll find that it's a melanoma.
Okay, suspected keratoacanthoma. Keratoacanthomas have been reported to metastasize. I haven't ever seen this but, from that point of view, it's often best just to cut them out. Curetting you could give it a four millimetre margin, it should be all right. Very hard to tell apart from SCC. Even if you did sure, histologically, you must have the central deep section to accurately diagnose a keratoacanthoma, which is why, according to the picture I drew there, if you do the pie slice, if you do the excision, if you do an incision, in all of those cases you’re getting what you need – a good piece of tissue, a deep central sample. Personally I don't curette and cautery these. And if you do traumatize them, they may rapidly regress. Punch biopsies will notoriously misdiagnose these.
Okay, cartilage sample. So this is generally, you know, you've got a high risk SCC or BCC on the ear (and you have to learn those features and look them up) or when you put in the anaesthetic you find that the tissue is actually adhered to the perochondrium (the covering of the cartilage) think uh oh, I might need to sample the cartilage. You can do a shave, you can do a scalpel, you can do a wide punch biopsy. You can also do this as a therapeutic procedure for chondrodermatitus nodularis helicis, that pressure effect you get. Main thing is, that does if you're removing the cartilage it means you are removing the perichondrium, that's the blood supply. Okay, the cartilage does not have blood supply in it, the perichondrium covering does, so if you're going to be doing a graft, particularly a graft, or a large flap, you need to be aware that if you're removing cartilage you may be mucking up the blood supply. Personally if I'm doing a graft on an ear and I've removed about 30% of the area, you know, strip the perichondrium of the cartilage out, you think uh oh this is going to impede the healing, and you may need to do some fancy technique like punch holes through to the ear tissue on the other side or change the thickness of your graft or your closure method. Again, this is advanced knowledge. It does have a separate billing code (cartilage) it's good to know that for your own sake, but of course don't be taking cartilage just to get more money, because you get audited for that sort of thing.
Okay, ulcers. Now, this depends a bit on patient selection, because a lot of these people with ulcers are vascular path, they're poor healers, and excision is not possible or ideal. Of course an excision would be great – that can be therapeutic if it removes the whole thing – but if we're just trying to diagnose what's wrong with the ulcer, incisional biopsy. So through to through with normal tissue might be good. If I'm suspecting malignancy I tend to sample the edge. If you sample the middle you'll just get slough and white cells and dead tissue. However, if you're suspecting funny organisms, especially Pseudomonas and you don't have a Wood’s lamp to shine on it, biopsy the centre, but you have to send it in a saline pot, not formaline, and send it for both acid fast macilli stain and MCS. When are you meant a biopsy ulcers? Well, I would say if it's persistent for more than two to three months, or if it comes from something like a thermal burn that increases the chance of being Marjolin’s ulcer, which is much more aggressive.
Question – Is saline pot a urine jar and saline soaked gauze? I just put in sterile saline. I just put in a few mils and I put it in a sterile urine jar. If you're out bush and it's going to take you a while to get this in, ring the pathologist and ask, because I know some people and they get a collection about once a week or once a month that gets sent off – so ring the pathologist or the lab technician if you have any questions.
As an interesting side note if you're actually doing an excision and you have redundant skin for a patient, you can actually store that sterilely in a jar with saline for I think about seven days and use it as a graft (obviously for the same patient).
Right. Blisters and inflammatory – I've group these together. You get all sorts of things. So, large blisters, for example, this is very key – get the edge of it – and when you take a nice biopsy or an incision, aim for three quarters normal skin and one quarter blister. That gives you the best diagnostic accuracy. Small blisters – if you can, get them out in toto (that means either with a trephine punch if they’re small enough for excise that's best). Inflammatory areas – avoid bits they've been scratching, avoid areas treated with steroids. And the chronicity, so how long it's been around, does make a difference. But that's the thing – in some conditions it makes it easier to diagnose, some conditions makes it harder to diagnose, depending on how all that is. So I normally take a new one and an old one. And if you think it's something crazy or autoimmune or strange and you want to do immunofluorescence take a biopsy of normal skin several centimetres away, so perilesional skin, for immunofluorescence. One big warning, if you ever have a rash non responsive to steroids, like it does not effect it at all, especially over a month, you know that's dragging it on, you need to check it and biopsy it in case it's cutaneous lymphoma. So rash, non responsive rash, yep cutaneous lymphoma. Punch biopsy is fine for that. Sometimes you get Paget's disease like from the breast or non Paget's from the prostate, which is very rare, sometimes on the abdomen, so these things can occur all over the place. So the point is you do biopsy it. It mimics inflammatory, cutaneous lymphoma mimics inflammatory things, they have dot vessels.
Okay, now a couple more questions – please describe how to biopsy vulval tissue e.g. lichen sclerosis. Okay. Consent the patient, offer them an alternative or referral. If you're going to do it yourself, three or four millimetre punch. Shaves may occasionally work but they take a while to heal they can be painful. Keep the area clean. Clean it with clean water. Generally it's okay. You might want to be a little bit consenting about scarring because scarring and can be painful.
Biopsy for lesions on lips. Depends what you suspect it is. There's a couple cases that we can go over. Got 15 minutes left.
Another question. I was under the impression that if you send in a biopsy they cut the sample in half to examine it. Interesting question. The technician should be able to see where a blister returns to normal skin I would think on the sample if it's big enough. And if they section it and they say well look I don't see any bullous tissue or separation, well you go, well yeah they may have missed it, so you have to interpret the pathology to see if they miss it. I don't think it's ever happened to me with a blister. I once had a melanoma that they sectioned four times before they got the point three millimetre piece that was a melanoma but, of course, the report said, you know, no nests of melanocites, so you always have to interpret the report against what you thought it was. If you're starting out, one of the best things you can do is take a photograph of everything, refer back to it if the diagnosis wasn't what you thought it was – you'll learn a lot about dermoscopy.
A couple more clinical questions. Young female not responding to topical treatment rash on the face – what kind of biopsy do you recommend? Depends how young they are, concerns about cosmetics, whether it's a child… Look, if we just cut out all the concerns about cosmetics and referral, and all that other really proper GP stuff, I would say generally a four millimetre punch biopsy will give you a good report on that or that or the perilesional skin for immunofluorescence.
Putting a suture in a sample like 12 o'clock should do it. Yes. Correct. Marking your sample with ink, marking it with the suture, marking it with a little nick, or marking it with liquid paper because that doesn't get destroyed in the processing – all of that helps.
Clinical information on the pathology request is as valuable as a tissue? Absolutely.
Do I put a nick at 12 o'clock? Yes, I always orient 12 o'clock to the vertex of the scalp anatomically. Look, it doesn't matter what you do, as long as you know what you do and you do it consistently – that's the most important message.
Multiple seb K on the trunk? Well if they have multiple seb K coming up all at once on the trunk, you've got to worry about the Sign of Leser-Trelat, especially if it's itchy, you're concerned about internal gastric malignancy. If it's just seb Ks and I'm not suspicious, I tell them to live with it, if they don't want to live with it, you can shave them off, you can full gerate it with a hyfrecator to peel it off with anaesthetic. Various things.
If pathology result confirms melanoma and you're asking for more marginal clearance, do I refer my patients to a specialist or do I do it myself. I refer probably two people a year to the specialist, but that's because I do this, all the time. You can do almost anything with a proper ellipse – that is your absolute workhorse – and then your next flap should be something like a rhomboid flap – for your first one to learn it, an ellipse… look, I had a friend who is a GP and he said he did skin, maybe, you know, a few hours a week, and he said, you know I'm a great skin doctor and one of the best in town (he had a bit of an ego) and said I do, I think, 12 to 15 flaps a week. I do skin full time I do about two flaps a week. You can close almost anything with an excision and that's also why they've changed the Medicare guidelines for billing, you know, based on defect size. You know, you can’t charge a flap without great justification unless it's bigger than a certain size.
Melanoma in situ, two millimetre margin enough? That's for diagnosis okay. That's for accurate diagnosis. Melanoma in situ they now say, if you can get up to 10 mils you do that – that's 10 mils clinical margins, not histological margins. That's because some reports say that 2% of the in situ melanomas come back – some say 25% which surprises me, I’ve never seen that amount (I wonder if doctors were undercutting). I think a lot of the confusion about the margins on this and whether it's 5 mils or 10 mils comes from facial in situ melanomas, because facial in situ melanomas have skips at the borders, they have skip lesions so you need minimum 7 millimetre histological margin for facial melanoma. I would clinically try to do 10 millimetres on the face or 10 millimetres anywhere else on the body.
Thanks for saying that about ellipses – I didn't realize I didn't need fancy flaps. Yeah, flap is get out of jail card. And look do time with someone, come and spend time, quite literally, if anyone just wants to come and spend time with me seeing flaps and grafts, I’ll line some up for you. We're trying to set up an RACGP mentor program where literally you can say I'm going to go spend an hour or a week with someone and learn how to do stuff – I think that's the best way to do it – see one, do one, teach one.
Someone is saying, if you have one lesion that's an SCC in situ… If you really know your dermoscopy, you can pick an SCC in situ. So basically with good dermoscopy you either know what something is or you don't know what something is. If you don't know what it is, you need to biopsy it. There are a variety different ways to diagnose invasive versus non invasive SCC. The invasive SCC, if you rub them between the fingers, feel thick, that's indurated, they're often tender when you laterally press on them, and dermascopically they may have features like a lot of excess scale on the surface, they may have white circles and white features. So, yeah, the pain on lateral pressure, the induration – those are the one they don't often tell you. Otherwise learn the algorithm prediction without pigment by Cliff Rosendahl – there's a good article on that online.
Right, melanoma of the nail unit. Again, a bit advanced, but just so you know. I think there's only about three people in Australia who do this, myself included. Just to illustrate how the melanomas work – statistically most likely on the big thumb. Very rare in kids below the age of 16 (very, very, very, very rare). You can always get in touch with me, get in touch with someone like Cliff Rosendahl – if we don't know we're talking about, we can always send it to Luke Thomas the world expert in Paris, who we know. But the point is, that little red circle in the top left is where the melanoma actually lives. There's never been a melanoma that has formed in the nail bed. Okay so that's the area need to sample. You need to sample the entire width of the discoloration. You have to pop up the nail, sample it, and then tie it back down so that you know it lives. High chance of nail distortion or nail loss with this. With new technology, like confocal microscopy, we might be able to use this to diagnose lesions better. But that's limited advanced stuff, so if you're not going to get funding for that, sorry. Yeah, I mean it's like two people in Australia who use it. Okay, but you try to visualize the pigmented matrix. Now, look, SCCs of the nail bed do occur, so if you get a distortion of the nail bed, progressive distortion, bleeding, think that you might need to actually biopsy the nail bed. Okay, not the now matrix at the top.
Bowen’s disease – question about topical treatment. Sorry I might have to brush over that one until the end.
Lots of questions about margins, and I agree they're hard to look up but let's talk about and do a few cases and then at the end I'm happy to sit around and talk about these different things okay, because we've only got eight minutes, alright.
So this one – just under two millimetre lesion on the abdomen of a first trimester, she was 24 year old, woman. This has been long standing present her whole life. In the first trimester this particular mole darkened in the bed, she said the other ones didn't. What’s your decision doctor? Type any answer you want and we'll have to whip through these. So, ideally, you want it removed. Are you suspecting a melanoma or not? Hello, Fiona – you want a two millimetre margin. Okay, now look, good rule with pregnancy you do get pigmentary changes, but they should all move in step, they may lighten, they may darken, they may become more defined, less well defined, but they should all do the same. This is a single lesion that has changed slightly. This was a melanoma in situ. Okay, so changing lesion in an adult, worry about that. You can do a biopsy with the two mil margin. You can theoretically shave it off, but, you know, the exam answer would be excision biopsy with two millimetre margin.
No, you don't have to avoid local if possible in the first trimester, not at all. You need to know your doses definitely later on in the pregnancy it sometimes interferes with cardiotocograph readings, especially if you're using the adrenaline, but no small dose – look how much anaesthetic is this going to take? Point 1, point 2 mils.
New mole in an adult, is it suspicious? Yeah any changing lesion in an adult is suspicious, so look at chaos and clues, look at the exceptions to the rule. Raised lesions you don't monitor. New or changing lesions in an adult you don't monitor, unless you know what it is. If you don't know what it is you biopsy it or you refer to someone else.
Why don't we do a 10 mil margin? Well, first of all, you don't want to give her a big scar unnecessarily. If it is an invasive melanoma, you then muck up your sentinel lymph node biopsy if you need to do one – that's why – you preserve the local tissue for the testing.
Do I have a resource for checking margins and lesions and best treatment? Yeah, go to the Melanoma Guidelines, the Cancer Council, and the Keratinocytic Cancer Guidelines – bit of a hefty read. They're a bit of a guideline more than an absolute rule, but it does give you a good breakdown. If we have time to do another lecture in the year we’ll go through all this, okay. So sorry I know it's very vital information, just in the interest of time, we got an hour.
Okay, this one. Four millimetres. Does it have any invasive features? First of all, do you suspect a melanoma or do you not know what it is? Yes, ideally, remove it with two mil margins to rule out melanoma. Now, if you do a lot of dermoscopy, this is actually tar – this is bitumen on someone's skin. You can tell because it's sitting in the folds and the creases. Always, always try to wipe something off okay either using these goo remove things or alcohol. Goo remove gets rid of a lot of sort of mucky stuff. I actually had that same doctor I knew once cut out what turn out to be dried chocolate ice cream on the belly of an elderly man. Wipe the thing – you need to wipe it to clean it anyway, give it a good wipe. Just a little learning point here, but still look I wouldn't be angry with you, if it didn't wipe off and you said I'm dead said that's a melanoma you know that's how you see it. Okay, we better rush through.
Okay, this one – how would people biopsy this? Yep, if it's a suspected peratinocytic cancer, you could do a punch biopsy. If you think it's an amelonotic melanoma you would do an excision with two millimetre margins as best you could guess. Obviously, if you punched it and they said there were melanocytes, you’d go oopsy daisies, that's probably a melanoma. Yeah, so it depends on what your suspicion is, but as long as you interpret the results versus your differential you won't go too far wrong. And just think about it. Ring the pathologist if you have any doubt about what's going on.
Okay, this one was in the armpit of a 60 year old male, been present for let's say five years. This was about two weeks ago, this one, I think. So, yeah, bit of a tricky one. You might think this is a seborrheic keratosis at first glance, but you've got to look up your criteria for seb K’s.  Seborrheic keratosis should have a well defined border the whole way around. There should be multiple ones that look the same. So this is a highly invasive melanoma. If you look at the periphery, like if you look down at six o'clock and five o'clock, you'll see that there are little dots and globules – that's quite characteristic of a melanocytic lesion, a lesion comprised of melanocytes, they form nests. Seb K’s are not formed of melanocytes. Okay, good. Good answers.
This is probably similar to the previous ones. Again, it might be hard to gauge the margins is all on saying. This was one that, this came up on a gentleman's back. It's been treated with steroids by the GP for I think five months, unresponsive. You know, it's considered to be a rash. There are some dot vessels there which could indicate a rash. Well, look, this was a melanoma. Again, not responding to steroid over a month, you biopsy it. If you did a punch it would have said melanocytes. If you did an excision or an incisional biopsy they would’ve said, yep, this looks like a melanoma. But before you do a therapeutic margin on a melanoma, make sure you actually have taken the whole thing out to work out, you know, how high risk, it is.
This is just an example. I would say, are you going to sample the brown bit on the left or the pink bit on the right? Well look sorry terrible photo that, but you can see by standing back that that's actually a large lesion with an area of hypopigmentation, hypopigmented melanoma, so you just have to say, look, we want to take the whole thing or a sample of both areas. Remember, you see pink, look for brown; you see brown, look for pink.
This is a one on someone's face. Might be too large to in one go. It's got features of melanoma on the dermoscopy – that's a perifollicular rhomboids and asymmetrical perifollicular pigmentation. If this worries you, start looking at these. And special rules on the face and the neck guys for melanoma. You have to learn a couple of simple criteria for melanomas on the face. The terms can be a bit confusing. Look, ideally, cut it out with two mil margins if you suspect a melanoma. If you can't do that, for whatever reason, because it might require a flap or graft and he's a farmer, what’s your get out of jail free card (apart from referring him or sending someone like me a photo)? Well, incisional biopsy, shave, deep shave, or something like that. I think I did an incision along this guy at to the most suspicious areas and I told the pathologist there is perifollicular pigmentation. Yep, it's a melanoma.
All right, sorry, in the interest of time (I don't like going over time)… This is a Merkel cell cancer. You might think it's a BCC or an SCC. What happens is when you biopsy this you need to have a bit of a clinical suspicion. High death rate – like third highest cause of death for skin malignancy for men. It looks a bit like a BCC but doesn't quite look like a BCC – doesn't have palisading. So the pathologist might get you to take a bigger sample. They need very specific stains for that.
This is a lip one… (Sorry I don't know why things are zipping, away unless someone's trying to speed me up). Look, lips, they’re either melanocytic, which makes it suspicious of cancer, melanoma, or ahhh…. Sorry, I don't know what's going on, we might just be flicking through to the end. Okay, all right, we'll finish there, then I will stick around for the additional questions.
Chantelle Vonarx: Okay, great, thank you Dr Hudson. So, as you said, he’s happy to stick around answer some questions, but just because we have reached that time point, just wanting to let people know if they do need to leave that's fine. I’d just like to thank you all again for attending. Also thank you to our sponsor, Ochre Health and Recruitment. Now just a reminder to please complete the evaluation form that will pop up a new window once you close the webinar session – it takes no more than a minute to complete. And certificates of attendance will become available and your CPD statements within the next few days, but for any non RACGP members who'd like a certificate of attendance please email But for now I'll hand back over to Jeremy for any other questions he wanted to respond to.
Dr Jeremy Hudson: Okay, thanks guys. Yeah, we're going to have some educational training with RACGP (sorry, I think my mouse is going a bit mad). Okay, so RACGP, we've got the Primary Certificate of Dermatology, which includes the skin cancer component. There’s also the private groups like SCCA Health Cert, or you can look it up online, right. I mean there's this great stuff. If you're going to learn your first algorithm, learn three point checklist for pigmented lesions, then move on to chaos and clues, and then you move past that eventually – takes about a couple hours or two days of work to get good at say three point checklist with pretty good accuracy for melanoma and pigmented BCC. Pink things unfortunately don't really come under that algorithm. But, yeah, there will be courses, there will be some face to face stuff this year, there will be some online Zoom stuff. Happy to do further talks if anyone wants to do it.
You've logged in late? I'm sorry to hear that. Hopefully there will be a recording – I'm very happy for people have this as a resource to review.
Chantelle Vonarx: The webinar is being recorded and will be put on the RACGP site.
Dr Jeremy Hudson: I'm just going to remove this mouse so it stops being naughty – maybe this will fix it – bad computer.
Okay, great. Yeah. I try to keep things relevant and concise, thank you for that, because I know you just want to know the basic useful practical stuff, don't you, without chewing through all the data and the studies. Obviously, a lot of this is my own opinion, but it's based upon research. Now any questions that I did not answer?
Health Cert versus Skin Cancer College of Australasia? There's also a Masters via UQ. Seriously they're all very well done. Very well done. I wouldn't have any hesitation doing any of those – at the end of the day, whatever suits. You can always start off doing the basic certificate and then branch out if you want to.
When do the courses start? You’d have to check their website. I think they usually run about two intakes per year. But there's a lot of great online resources, okay. And colleagues – don't ever hesitate to reach out to someone.
Thank you for all the ‘thank yous’ but maybe we'll just stop. I appreciate them, but we can have a quick chat about the clinical questions – we might have to resubmit the ones I didn't answer to save me chewing back through this so.
Okay, Bowen’s disease lower leg. I think, from memory, you said, there was a 20 mil Bowen’s disease on the lower leg. You need to know your dermoscopy to see that there aren't signs of it being invasive. You need to feel it to make sure that no indurated bits. You’ve got options with Bowen’s disease and IECs of the lower legs. Look, if you can cut it out that's fantastic – you may want to do a flap, you may want to do a graph. If that's not a doable thing, you can curette and cryotherapy – that may heal poorly though in someone. You may use Efudex for six weeks, but if it doesn't respond or comes back you really need to cut it out. So recurrent IECs are high risk. SCC forming in a field of IECs is higher risk – you need to cut that stuff out.
Questions, questions, questions… Best dermatoscope? Look I would start off with a, hmmmmm, DL2 maybe. Look, you can't go too wrong. Don't get sucked into all these expensive new dermatoscopes with five more LEDs. They've mastered the dermatoscope years ago. You might have to spend something like $500 upwards. You can get attachments for iphones if you're doing a bit of casual work, iphones or samsung's – I think it's an IC10 where you just snap it onto your phone and you can see it. Just be aware that if you are using the phone attachments, due to the receiving chip for the phone, you don't see as much blues and greys which are very powerful tools for melanoma diagnosis. But it's not bad, okay, it's not bad.
If you're going to do it all the time, I use a DL3, the Heine’s are also very good. It comes down to contact or non contact. Obviously you want a non contact polarizing one so you can speedily go over lots of lesions. You should never be doing a skin check partially – you always need to have full skin checks – you need to look at everything. And then you can put it contact if you need to be more specific about a few things dermascopically.
What's your go to resource for practicing dermatocscopy? Well, I sort write this stuff now, to be honest. I just Google it now, because I look for fairly in depth stuff. If you're starting off, RACGP publications are great – they've got a really good I think 10 page handout on chaos and clues and prediction without pigment – that gets you really far. But that's pretty in depth, you need to chew through that over a few evenings. I had a really good dermoscopy book called the Three Point Checklist Book, I think, where basically the three point checklist deals about blue or grey structures, deals with atypical network, and I’ll be blasted if I can remember the third one under pressure to be honest – maybe someone will have to remind me – I’m a bit embarrassed I can't remember it. But the point is they have pictures in this book – they go through about 100 cases and in every case is a nice big photo pointing out what's an atypical network, what's a blue or white structure, and I think the other one was asymmetry in colour or structure. Okay so I answered that correctly.
Do I use sodium bicarb with local anaesthetic? Yes. It's about nine units of local anaesthetic, one unit of sodium bicarb – that buffers it, makes it less painful, especially if you slowly inject it. It will denature the anaesthetic if you leave it in overnight, so you can't pre-prepare it unfortunately. So you need to have a sterile sodium bicarbonate container that you draw out of. If you add too much by carb it will not make the anaesthetic work too well either – pH changes like infection and bicarb it will not anaesthetic work as well. So if you're putting local in an abscess, you know, which is acidic, it might not work too well. And again, the concentration of local anaesthetic – look, 1% is good, you can go down to half a percent, which is actually very effective as well. Very, very effective, half percent. The stronger concentration doesn't work better, it lasts longer, okay, changes the duration of action, especially if you doing a nerve block.
Thank you – asymmetry – you deserve a bonus point for correcting. Okay.
Okay, the lip one – alright, so we're talking about that pigmented lesion on the lip. Now, one very important thing is apparently, statistically, most of the benign melanotic macules on the lip occur in the central third – if they occur to the lateral third you get a bit more suspicious. The benign ones tend to have features like brown dots running in linear arrangements, and they should not have any other features of chaos, and they shouldn't have any other of the features of chaos and clues like weird vessels, white scar like depigmentation. Now some people say don't shave a lip because it's painful and it takes a long time to heal – that's a rule of thumb. You can treat it with Vaseline. It is sore, but it gets better. You get a good sample off that. If you did biopsy it and you did a three or four mil punch, I don't tend to suture those – they do scar a little bit. If it's a benign melanotic macule, you won't see all these melanocytes. If you see melanocytes, you think oh gosh could that be a melanoma. So what you could do is even biopsy it and say this is a pigmented one on the lip, okay, not on the skin, but on the lip – this is a special case – and you can say to the pathologist please rule out a melanocytic lesion particularly a melanoma, and that will give them a good bit of information. Hope that answers that.
Love to discuss proper topical treatment – yep, very happy to talk about that at some point but might be best to do that one last, sorry.
Dental anaesthetic for skin excision… Well you’ve basically got amide and esters. I just use lignocaine. You wouldn't use one or the other unless someone had an allergy. So I don't quite know what you mean by dental anaesthetic, unless you're talking about the topical anaesthetic, like topical gels and creams. You can use that, especially with kids. It helps a little bit, but it takes about three hours to really work, you have to occlude it on the skin. Same stuff you'd use to put it in IV line in a kid. But do remember the elderly, they can absorb that to lignocaine toxicity, so you really need to know your doses, with adrenaline and without adrenaline. You really need to know contraindications to adrenaline, okay. Now you can use adrenaline in the finger, on the lip, on the tip of the nose, okay – because they’ve basically proven that because someone accidentally injected adrenaline, pure, like basically proper adrenaline, into a finger and it was fine (this is in the A&E at some point). But you wouldn't do it on like the tip of the penis, that's the one spot that I definitely would not do it. It takes 10 minutes to kick in anyway, so you don't use adrenaline unless you're going to wait 10 minutes, and then it reduces bleeding. The anaesthetic, the local anaesthetic, takes point three of a second to work. What else? Oh yeah, so contraindications to adrenaline. I mean look that up, it's like people who are ASA (that's an anaesthetic category) two or three, people who've had heart attacks or strokes, you really need to minimize your adrenaline to a max of three mil if it's 1% adrenaline. If elderly people over 70, they have a reduced liver function, be very careful, I mean don't give it if they're on tricyclics or MAOIs – you can get sudden death from that – no anaesthetic in them. Not many doctors know that surprisingly. I mean, I've seen colleagues give it to people on TCAs and MAOIs, but I would never do that. I know I'm getting into the jungle here of knowledge, but I think it's probably a valid point.
Shave biopsy for pigmented – excisional with 2 mm ideal? Several patients with multiple highly dysplastic nevi – is it appropriate to use deep shave for diagnosis? Okay. Dysplastic nevi are now grouped by the WHO into low grade (which used to be low and moderate) and high grade – so low and high. If it's high grade, you usually do that with five millimetre external margin for curative purposes. Maybe two mil margin for the other ones. The reason why a bit more wary about the severely dysplastic ones is because not all pathologists use the same criteria to differentiate severely dysplastic nevi from melanoma in situ – only about 12% use the same criteria surprisingly. There's a list of about 20 criteria they might commonly use. But can you shave them? Look, severely dysplastic nevi should not be invading, okay. If it's invading it's a little bit bizarre, it's probably a melanoma, so a shave would get you the diagnosis. The point is, are you getting the entire lesion with a two mil margin of skin? Let's say you did segment a severely dysplastic nevus, you'd probably cut it out anyway and send it for further testing just to make sure it's not a melanoma. So not ideal, but you know dysplastic nevus dyslexic has features that look pretty old. Look not the end of the world, I guess what I'm saying is you don't need to be doing a deep shave, you need to be doing an adequate shave (and by deep shave I mean you don't really need to be going down to fat – you go down into some deeper dermis). But, yeah, look, I mean I had one guy and he had I think we had to take like 22 things with him, and could not take the anaesthetic because he had various co-morbidities – we just did all shaves. I think one guy six were melanomas, none of them were segmented, so… You have the guidelines, you have the party line, especially for exams, and what you teach registrars, but you know you’ve got a bit of leeway when you kind of do this thing a lot.
Large leg excision wounds take a long time to heal… explaining healing time to patient and dressing as best, especially an old people. Okay, consent is key. So older people with sauserization, curette or cryotherapy, you have to say look average healing time is three weeks, could be up to two months with you, you could have a chronic ulcer and I'm sorry about that, but it's a possible consequence. You might get sued if you don't consent someone about these issues. If you're going to be doing lower leg below the knee, you always need to assess people for vasculopathy. Smokers, get them to stop smoking. Can you feel the dorsalis pedis in the posterior tibial? Is there hair loss? Is there evidence of varicoseties? Is there diabetes? You need to know this stuff. Is there oedema? Do they need to keep the leg up? So basically, yeah, basic rule, keep the leg up, you can dress it with something like algisite, which needs changing every three days, or a gel called… solo… can't remember what it's called… they can do frequent dressings. Some people, I do let it dry up to stop it oozing. Lots of factors involved. Like an edematous person, you may want to get them stockings before you operate. So that's another issue, you can probably look up about preoperative assessment of patients and cutaneous surgery – sorry, it's a lecture on its own, basically. I hope that answered some of that.
An email address where we could ask you who's good in our area to learn about skin medicine? We're kind of trying to sort that out. I mean you can either go through the RACGP and email me through that way, or you can email me (don't share this with patients, but your doctors I'm happy for you) you can email me at I'm happy to talk to people, and you can ring me all right if you're really stuck – just Google me and give me a ring, okay, we're all here to support each other.
Solosite, thank you, solosite is that gel.
I'm still happy to answer questions – Chantelle is being so incredibly patient. Did I miss any questions people want to ask? I'm trying to get through all of them.
Chantelle Vonarx: From what I can see you’ve answered everything, but if there's any outstanding – if you've asked a question that we haven’t answered – if you want to just quickly type that into the chat or the Q&A again so Dr Hudson can cover that for you, that'd be great.
Dr Jeremy Hudson: Don't be shy. Okay well look people seem pretty happy. And thanks a lot everyone – every question is a good question, right. I mean you're only silly if you don't ask. Like we all have tired days, that's what colleagues are for.
Oh, Bowen’s excision margin. It depends on where it is. It's higher risk in some areas, but I think if you're talking about, you know, Bowen’s in a non complicated area, if it’s well defined… it depends how big it is. Look, you could just do like a three or four mil margin, something like that, that's reasonable.
But, yeah, margins are a very good question, because when I started, I spent hours looking up websites and it was just so hard to find consistent margins. I can definitely get some stuff together for you guys, if you like, about topical therapies and margins at some point.
Yeah, histology module. Look histological margins are separate to clinical margins, alright. So some people go purely based off clinical margins (so what you measure with your ink). And some people like Ian McCall I believe who does a great dermatology course, he does histological margins. So, for example, if I have a basal cell cancer and you have a histological margin with a good pathologist and you're confident about your clinical margin and they say you've got a one millimetre clearance, you know that might be sufficient for a basal cell.
What about ablation for non MM skin cancers? So Keratinocytic cancer with laser? Well, look, yeah lasers are very expensive – I don't know a GP who has one. One of the plastic surgeons in town has one and I'll sometimes refer like a lip to be lasered. Don't think that the plastic surgeons are being precise about it – they don't do dermoscopy, they don't use a dermatoscope, they basically just ablate the entire lip and call it a day. So I don't see it as a common rule so sorry I don't know too much more about laser.
When you're looking into the more special treatments for things you're looking at areas, perhaps like lips, and also genitals, like Bowen’s disease on the genitals as a bit of a special case – you don't see it often – more virally related, I think you can use more varying topical therapies for that, but I've never seen it.
Oh yeah someone did ask a question about I think about labial or vulval lichen sclerosis, or something like that. Look, any suspicion of that needs management in a specialist clinic for ongoing management. It can be a clinical diagnosis, if you want to do a histological diagnosis, I would think a decent sized punch biopsy would diagnose that. You need to have clinical suspicion – it's a very serious thing.
Okay, what are some things I asked of patients to prepare for a full skin check? Yeah, you want to take off makeup, yeah. Nail polish, generally yes. If they don't manage it, look, sometimes you see the matrix – remember the matrix and the proximal part of the nails when you see the initial coloration – so if they don't have coloration of the proximal part of the nail that you can see it's usually not an issue. Or I say when you change over your nail polish bring it back and I'll have a look. Fake tan can definitely make things look odd. You have to be very careful with tattoos, very careful with tattoos, especially because we know that, you know, if you break up a tattoo you actually find remnants of the tattoo in lymph nodes – that's a bit scary.
I send them to obstetrics and gynaecology – yep great answer for the vulval ones. Remember the gynaecological people are experts at this. I do look at vaginal things or penal things or genital things. But the question is, if you can’t refer them or it's going to be very, very tricky, what’s your get out of jail free card? Well it's getting a histological sample. If you don't know what to do, ring the pathologist and say I don't know how to sample this, this is how big it is, this is what I suspect it is, they'll tell you precisely what they want. So that's why you need a good relationship with a pathologist. If you don't have one, make one. The more you talk to them, the more they like you, because it improves their accuracy as well.
Ah, yeah, radiotherapy works nicely in patients with extensive areas of SCCs you can't excise. Yes, but you tend to limit that to people over the age of 70 because you tend to get severe radiation side effects after about I think 20 years. So there is a bit of an age thing there. It's very good at clearing extensive actinic keratosis or even early SCC on the scalp of men. Fractional radiation. I've referred one person for it.
After excision of SCC and BCC, if report comes with the margin of 0.4 mils clearance what do you do? I would say that's inadequate. One caveat to that, when I might say 0.4 is adequate, is let's say it was a beautifully tiny well defined nodular BCC and I rang the pathologist and they said oh look that border is so well defined I'm confident you got it with the point four mil clearance – great you know you're good. That's an exception. Generally speaking, look, some people say you can get away with 0.5 mil for BCC histological clearance, a safe rule of thumb is one mil. And you need to know your high risk stuff. So if it's anatomically high risk, in the age zone of the face, if it has infiltrative patterns, you need to get good clearance on that. If it has cystic features like little white cysts, that tends to be well defined deep, but it does push deep rather rapidly, especially in fusion planes on the face, like nose and cheek so. You get this clinical knowledge, you accumulate it, you can then usually get it first go.
All right. All our brains are empty or full. Time to go get a drink or so see your family maybe, give you a partner a hug.
Full. Someone said it's full – fantastic. Okay, well, lovely. Thank you all so much. Fantastic questions. Just to reinforce, anyone who's interested in skin, please just feel free to sign up for the RACGP special interests. It doesn't mean you have to attend meetings, but at least if you want to say something or be heard about policy and have questions, you're free to do that,  you'll get updates about skin stuff.
Another comment – I just listened to a HealthED podcast on vulval disorders – always biopsy lichen sclerosis to confirm diagnosis. Is that all you do or typical appearing case that responds well to topical steroids, reasonable to monitor? Now, medical legally always refer lichen sclerosis. I mean, yeah, biopsy is great to confirm. I more mean if you have a strong suspicion, you can just refer it. Yeah, always err on the side of conservative referral for lichen sclerosis – you should not be managing it yourself as a GP, you put yourself in big risk for that.
Full to the brim. Fantastic. Thank you very much. Okay guys well have a great evening, hopefully. Have a great Friday and a great weekend and we'll touch base soon.
Chantelle Vonarx: Excellent. Well, thank you Dr Hudson. Very informative and I think everyone enjoyed that, so thank you again. And thank you again to our participants. And with that I'll end it so everyone can get on their evening. Thank you.

Other RACGP online events

Originally recorded:

4 February 2021

This instalment of the Rural Health Webinar Series will explore practical techniques that rural GPs can use to sample skin lesions and make accurate diagnoses. Through a series of case-based discussions of lesions seen in a week of general practice, participants will gain an understanding of the techniques that can be used to sample lesions in a rural practice (including their limitations), as well as which sampling techniques should be used for specific differential diagnoses.

Learning outcomes

  1. Discuss the techniques used to sample lesions in a rural practice, including their limitations.
  2. Identify which sampling techniques should be used for specific differential diagnoses.
  3. Apply knowledge to common lesions seen in general practice
This event attracts 2 CPD points

This event attracts 2 CPD points


Dr Jeremy Hudson

Dr Jeremy Hudson is Chair of Dermatology for the RACGP, and a Senior Lecturer in Skin Cancer Medicine and Surgery for James Cook University. He is also the Clinical Director of the North Queensland Skin Centre, a research based clinic in Townsville, and has a strong interest in medical education and improving clinical guidelines. He has spent most of his career as a rural and remote GP before specializing in skin cancer.


© 2021