Hi, this is Jane Grankels for one last time to again share with you when and when not to use confocal as well as some of the other technologies that you've learned about in this course. Again, I have no relevant disclosures to share. So when do I use and recommend that you use confocal? It's a virtual biopsy. So anytime I want to avoid surgery or completely, so sometimes I often use it in superficial basal cells that confirm the diagnosis, and then I treat with immuno or chemotopical therapy. Or if I want the patient to only have one procedure, one excision, or one mose, not a biopsy, and then another procedure, which is important for older patients and for lesions that are on areas that are cosmetically sensitive. So again, the face, the upper chest, the upper back, the upper arms where people can get thicker scars are cosmetically sensitive areas. And so a lot of times patients don't want us to biopsy or they're hesitant. The other area that I try to avoid doing biopsies are the lower legs, but particularly in older patients and diabetics. A simple biopsy can sometimes end up in a chronic ulcer that's difficult to heal. So I also try to avoid biopsies, obviously in general and diabetics and patients who are immunosuppressed and fearful patients, children, pregnant women, just in general anxious patients. Very often, this is totally a painless technology. All they have to do is lie still for a while. And even children, if you amuse them with a video, can lay still for as long as is needed to acquire the images. And then I've had patients, and I'm sure all of you who are listening have had this experience where they refuse a biopsy. They just biopsied out and they just don't want to have another biopsy and they put up a fight. Well, you can do the confocal and if the confocal is worrisome, show them why it's worrisome and then most patients will agree to surgery. So again, this is particularly true of the cancer-prone patients and patients with many atypical nevi. And I use it routinely when I do topical chemo or immunotherapy or cryotherapy for certain lesions to make sure the lesion is resolved. When I've used a micro mode for lenticomaligna, I follow it with routine confocals from time to time to make sure there's no recurrence. We already talked about in a previous lecture, identifying the correct biopsy site if the patient doesn't remember and there's not a picture that's sent along with the patient or in your chart, or identifying margins before a procedure. Now the obvious issue is it can't be used everywhere. So where can't, when would you, I recommend you not use confocal. Obviously, palmar, plantar, or nail area are not a great area. The thickness of the stratum corneum makes this technology not very useful because it doesn't, by the time you penetrate deep enough, you may miss the pathology because the stratum corneum is so thick. And the other problem is a hairy scalp, the hair will cause a lot of backscatter of light interfere with the imaging. If the patient allows you to shave the area, then you can use it there. And the other problem, and we already alluded to this, is areas that are very narrow or have concave anatomy, like between the fingers, the finger webs, around the ears, around the nose, the wide probe, the tip of the wide probe, traditional confocal, the head is relatively large and it requires a flat surface to make contact. Now you can use the handheld there in most of those areas with a smaller probe, but those areas are not amenable to the traditional confocal microscope. So that's the first, the first pitfall is anatomic site, you can't use it everywhere. The other areas that you wouldn't want to use it are ulcerated and crusted areas because it wouldn't, unless you remove that crust. There are other pitfalls. Obviously if you suspect the pathology is deeper than 250 or 300 microns or below the papillary dermis, this is not the technology you want to use. You might want to use OCT or ultrasound. It can be difficult to distinguish an AK from a squamous or Bowens. So, and I'll explain to you why that is. And finally, the fourth pitfall is that, remember I told you that not only are melanocytes refractile, but Langerhans cells can be, when they're activated can be refractile and that you can overhaul something, a melanocytic lesion, if the Langerhans cells are activated. Let's talk about the third pitfall, differentiating a squamous cell from an AK. Well, the confocal features of squamous cell and AK are pretty much identical except that in an AK it's not full thickness. And the reality is full thickness can be best evaluated in a vertical section, not a horizontal section. So, a vertical section will show you that here it's only the lower half or two thirds of the epidermis that's atypical. It's not full thickness. And depending upon where your technician gets her first mosaic, you may already be into the atypical squamous epithelium if she gets her first mosaic below the granular zone or just at the granular zone. So, you're very dependent on where the first mosaic is acquired. Now, what I do when I am evaluating an atypical squamous lesion, I've identified an atypical honeycomb pattern, so I'm worried about an AK versus squamous. I go to the bottom of the lesion, make sure there's no invasion or involvement of the dermis. And then I go back up, I try to determine if the top of the epidermis is involved or not, or if the adnexa are spared because in most AKs, the adnexa are spared. The fourth pitfall are the dendritic cells. So, in the epidermis, there are two refractile dendritic cells, the melanocyte and the Langerhans cell. And they can look identical, and they can be very difficult to distinguish from each other when the Langerhans cells are activated. They have to be, the burr-backed granules become refractile when the Langerhans cells are active and reactive. And the most difficult problem comes up with the pigmented Bowen's disease, where the clinical differential may be a lenticomaligna, pigmented AK versus pigmented Bowen's versus lichen planus, like keratosis. And the Langerhans cells we now know are activated in that lesion and can very much mimic dendritic melanocytes. So this is a patient, 68-year-old lady with a history of melanomas and basal cell, develops this pinkish tan lesion on her leg. And the dermoscopy is not that helpful. It shows a brown structural zone, which you're not, you know, is that lenticomaligna in situ area? You're not sure. You have dotted vessels, and dotted vessels can be seen in Bowen's or in melanoma. You have some brown oval structures, which makes you think of a pigmented Bowen's, but you have a faint reticular pattern at the periphery here. So you're not sure. So you go to confocal. And the confocal shows, lo and behold, you can see that there's an atypical network pattern, you know, atypical honeycomb pattern in the background. But you also have focally this increased number of pagetoid refractile dendritic cells that happen to be Langerhans cells, but they certainly can look like Bowen's disease. How do you determine it? It's usually only focal. It's not confluent, and the atypical refractile cells don't go down hair follicles the way they do in lenticomaligna. But you can go down the hopper and fall down the pitfall and overhaul something lenticomaligna when it's only a pigmented Bowen's disease. The other thing, obviously, you look for the atypical honeycomb pattern. You look for parakeratosis, and you look for the buttonhole sign, which are indicative of more Bowen's disease than melanoma. But again, this is a pitfall that you have to be aware of. And this was the biopsy of that lesion where there's clearly atypical squamous epithelium, and there's diskeratotic and necrotic keratinocytes. When you do a CD1A stain, you can see these dendritic cells throughout the epidermis that are also positive with S100, but are negative with melan A. Melan A only lights up the melanocytes at the DE junction. So we know these are Langerhans cells, not melanocytes, and this is clearly Bowen's disease. So in conclusion, I just want to try to talk about the all three technologies together. So confocal gives you a horizontal image up to 8 millimeters in diameter, gives you cellular resolution like you see under the microscope. You can read it in real time if you have the capability. It doesn't give you deep penetration. It only goes into the superficial dermis, but there are CPT codes that are available. OCT is very different. You don't get cellular resolution. You get 3D images with a large overview. Again, like confocal, you get real-time imaging, and the advantage of OCT is deep penetration. So these two technologies together would show you cellular resolution and depth, which would be Eureka. Would give you all the information you need before you went into treat a lesion. And ultrasound gives you a wide panoramic view that can be even 2D or 3D, and the depth is variable depending upon the probe that you use. But again, like OCT, no cellular resolution. It, again, like RCM and OCT, you get real-time imaging, and you can see the blood flow imaging. And ultrasound does have CPT codes. When to use it? Well, I've gone over this with you in previous lectures. RCM is a virtual biopsy. I use it all the time in my atypical nevi patients and for non-melanoma skin cancer. I use it in cosmetic areas, areas with poor wound healing, patients who have a history of poor wound healing, like diabetics and immunosuppressed patients, fearful patients, patients who adamantly refuse biopsies, cancer-prone patients. I use it post-treatment to follow my treatment with topical chemo or immunotherapy to identify the correct biopsy site and to evaluate tumor margin. So lots of times that I can incorporate this into my practice. OCT is also like a virtual biopsy and is most helpful to evaluate the architecture and the depth and the breadth of the lesion. It incorporates flow and movement into the imagery. It is mostly used right now for basal cells and to study dynamic blood vessel displays. Ultrasound has many applications. It can measure tumor thickness, depth, and borders. It can be used after surgery or cryosurgery or laser treatment for a non-melanoma or melanoma skin cancer. It supports the diagnosis. It's used in identifying and managing vascular anomalies. It's also used to monitor treatment in sclerotic disease processes and inflammatory disease processes. It is used in supporting the diagnosis and staging and management of H. nereus operativa. It can also identify exogenous components like foreign bodies or cosmetic fillers. And finally, it can be used to evaluate nails in both systemic diseases and specifically nail bed lesions. And finally, what are the limitations? In all of these entities, the machine is quite costly. You need to be trained for confocal. As we mentioned earlier, it can't be used in a crusted lesion or an ulcerated lesion, a hyperkeratotic lesion, or a nodular lesion where you think the predominant pathology is in the deeper dermis, doesn't extend up to the epidermis. It's not ideal for acral or scalp sites. And again, we talked about the fact that since you're using a light-based technology, not sound waves, hyperkeratosis is difficult to penetrate. OCT, again, similar limitations to confocal, including the fact that it has poor cellular resolution. But the main limitations is cost of machine, training, and it doesn't work well in hyperkeratotic areas. The ultrasound, again, cost of machine and training. The main limitation, it's not very good for thin lesions or just very thin epidermal lesions. It can overestimate tumor thickness by making the tumor look thicker because of the peritumoral inflammation. The good news is that ultrasound, however, can be used in ulcerated or hyperkeratotic lesions because sound waves can be made to penetrate those areas by moistening the lesion with a gel. And so, obviously, my expertise is in confocal microscopy, but all of these images can be added to your armamentarium of technology that can enhance your patient care, and you can replace the need for surgery, and in some cases, the pathologist, by using a confocal microscope. And I thank you for your attention and your interest in imaging for the diagnosis and follow-up of skin cancer. Thank you very much.

confocal microscopy

dermatology

virtual biopsies

patient care

imaging techniques