Hello everyone, welcome to the next chapter about Bézacer carcinoma. Bézacer carcinomas compared to healthy skin present quite differently. Therefore we will first review the healthy skin. So how does healthy skin look like in OCT? We have a very small, thin stratum corneum and then the underlying epidermis, separated by the dermoepidermal junction from the dermis. In the dermis there are blood vessels and you can recognize them not only by elongated structures but sometimes there are roundish ones. The entrance signal is much more regular than it is in some other lesions, for example like ectinic keratosis. Bézacer carcinomas also have some typical criteria. The first one for example is the thin epidermis. You can also see a dark ovoid nodule surrounded by a dark peritumoral rim and a pale peritumoral connective tissue. Here too you can see the dilated blood vessels. These are typical structures of a Bézacer carcinoma, more precisely a nodular Bézacer carcinoma. So let's have a look at all BCC criteria in OCT. First we have the thickened epidermis, also called pearl chain-like structures. That is very typical for superficial Bézacer carcinoma. But we will also have a thinned or thinner epidermis, which can often be seen in nodular BCC. Then we have the dark ovoid structures and sometimes there are ovoid structures with a bright center. And typical is also the dark peritumoral border and the lighter peritumoral stroma. Also black areas and cysts can be seen and this is what you have in a nodular cystic Bézacer carcinoma. There are also narrow elongated dark structures similar to fish shoals and also prominent blood vessels. The fish school-like structures are mainly found in fibrosing Bézacer carcinomas. But let's have a look at examples. Here you see a nodular Bézacer carcinoma. You can tell because you have dark ovoid structures and not just one, we have multiple. One here, smaller ones here, here, here, here, here and also one here. Some also have a partially lighter center, which you can see here. We have a thin epidermis and dark peritumoral rim and a bright peritumoral stroma. Sometimes you can also see small black areas like these, these and these. These are many cysts. If we go further, here you have a large dark ovoid structure with black areas corresponding to cysts and here a peritumoral dark rim. This is also a nodular Bézacer but a specific one, a nodular cystic Bézacer. You also have here a dark nodular structure and here and here and a small cyst inside here. It's a dark ovoid structure with a lighter center. You can also have this thin epidermis here and again a dark peritumoral border. This is what a superficial Bézacer carcinoma would look like. You have these string of pearls-like structures here, which are small protrusions starting from the epidermis. This is what I meant by school of fish. You find here these narrow, elongated, longish structures that resemble fish and these can be even this big. But in this picture, for example, they are really very small. They are close together, like you can see here. They are separate but they are very close together like a school of fish and this is a typical picture for a fibrosing Bézacer carcinoma. It's also the most difficult one to recognize in OCT. Now it's time for a little quiz. Is this an actinic keratosis or a Bézacer carcinoma? What would you say? I'll be happy to resolve that in the next image. Here in this image we have the actinic keratosis and in the image below is the Bézacer carcinoma. Why? Well, in fact, we have here a small hyperkeratosis and a broadened epidermis and a little broadened sternocranium. We have small blood vessels and a very nice regular dermoepidermal junction zone that you can follow with your finger. Down here we have the Bézacer carcinoma. We have the dark protrusion here but also, of course, here the dark nodule and with a dark peritumoral rim again. Then let's go to the next example. Another question. Is it certainly an actinic keratosis or is it a Bézacer carcinoma? Again, at the top there is the actinic keratosis and at the bottom there is the Bézacer carcinoma. Why? In the bottom image you have a dark ovoid nodule with a dark peritumoral rim. Again, you have a slight pearl chain-like structure like here and here and thus the diagnosis of a superficial Bézacer carcinoma can be made. On the top there is an actinic keratosis. There is a thickening of the stratum corneum in this area and a widened epidermis. Many blood vessels can be seen in the dermis and there is also a regular dermoepidermal junction. This is not an hyperkeratotic actinic keratosis. It's a very small one. Moreover, you can divide the Bézacer carcinomas according to scores. These are the results of a research group from Berlin which has classified Bézacer carcinomas on the basis of the criteria that I presented to you. There are categories 1, 2 and 3 but that is more of an academic nature. You can have a look at the paper if you want. If we look at the literature on Bézacer carcinoma in OCT, there are numerous criteria here that are indicative of a Bézacer carcinoma. I have already explained to you the most common criteria. What about accuracy in BCC diagnosis with OCT? OCT has a sensitivity of 95% for Bézacer carcinoma and a specificity of 75% so it's pretty good. If you look at a suspicious lesion with a naked eye, you are 65.8% correct that it is a Bézacer carcinoma. If dermoscopy is added to the diagnostic procedure, the result is 76.2% and with OCT you increase your accuracy to 87.4% which is quite good. Now if you study the influence of the localization of the subtype, the examiner and of the image quality on the accuracy which we did, we found that the localization has no influence on the diagnostic accuracy. However, scales and crusts have a negative influence. Nevertheless, OCT is better than clinical and dermatoscopic diagnosis because there you can also only say scale or crust is visible but nothing more. The examiner does not make a difference and the subtype can be diagnosed rather mediocre. Sometimes it is just difficult or is a mixed type. Now we turn our attention to the subtypes. Yes, there are certain criteria that are mainly found in certain subtypes. These pearl chain-like structures are found mainly in superficial Bézacer carcinoma. The dark ovoid structures with the dark rim and also the dark structures with a light center are found mainly in naudula piscis. But also the black areas cysts are found in naudula piscis and the fish school-like structures are quite typical for fibrosing Bézacer carcinomas. Now we move on to the subtypes. What do you think this BCC is? Do you find any criteria for a naudula, superficial or for a fibrosing Bézacer carcinoma? Let's take a closer look. Here I have the demoscopy for you. Still not sure? Maybe it's difficult. Here in this marked area you can see the tiny little fish. It's not so easy but once you look closer you can recognize that they are very small, elongated and that they're grouped close together. So this one is a fibrosing BCC. What kind of BCC could this be? Any ideas? I'll resolve it in a minute. Here you can see the demoscopy. This is a naudula BCC. You have the dark tumor nodule here in this area. It is roundish, it's partly with bright centers. We have this really large tumor nodule with a dark peritumoral rim here also. And of course we have the synth epidermis above because it's kind of compressed because of the tumor. So what kind of BCC do we have here? Not so easy at all but let's have a look at it. That is the demoscopic image again for this BCC. And here you have the big school and then here is a fish, here is a fish, here is a bigger one and so this is a fibrosing BCC. And what do we have here? This is how this lesion looks in demoscopy. This is a pigmented BCC. You can see that especially in demoscopy of course but in OCT unfortunately you cannot see pigment. But you can often see in pigmented BCC that there is a dark structure that has smaller lighter parts in it like here and here and here. And this could be a hint for a pigmented BCC. And what kind of subtype do we have here? Any ideas? This is how it looked in demoscopy. So this is still unclear, it's not so easy if you're a novice. So this was an adenoid BCC carcinoma that is often very bright. It's not so dark like the usual BCC carcinomas but you can follow the rim like in other BCC carcinomas and so you have a very dark large ovoid structure. But if you're not sure of course you're allowed to biopsy. BCC carcinomas can also be visualized with dynamic OCT showing these typical teleangiectatic blood vessels which we also know from demoscopy. And I just wanted to show you them as an example. And now we come to the differential diagnosis. If you see something like this you should not think of a BCC carcinoma but of a hemangioma. This is the corresponding demoscopy. Here it is clear of course. Here you have these lacuna-like vessels and then of course if you think about using the dynamic function of OCT over that you can see that these areas light up signal red because of perfusion. Here we have a dark cystic area and we have a light cystic area. You can also see that in the horizontal image as well here and here. This was a nodular cystic BCC and here this structure has already responded beautifully to imiquimod aldata therapy and then transforms and becomes necrotic. So that's what it looks like then and we do a lot of BCC monitoring under local therapy. And you can find something like this very often that if the BCC hasn't been completely resolved yet. So then you should do a follow-up a few weeks later. Psoriasis of course is always a differential diagnosis as well. You have here these dilated retriches and the plump papillary bodies in between and here a broadened epidermis and of course acandosis. And if you have the ability to use dynamic OCT you can see these dotted vascular protrusions into the papilla here You can see these protrusions in the horizontal image as well. They appear as the dotted vessels. Of course there is also the differential diagnosis of a sebaceous hyperplasia or of fibrous nodules which always look a little different than basic carcinomas. You really have these sebaceous bright structures in the OCT which correspond to the sebaceous glands. This is still an old OCT image that shows the image a little bit more bluish but it's the same for conventional OCT. The fibrous papule where you have these darker strands corresponds exactly to this in histology. Sometimes on the nose these are very hard to distinguish from basic carcinomas but they still have some other additional criteria. They do not show the BCC criteria and if you have the possibility use line fecal-focal OCT because it shows off the cellular resolution and makes it a little bit easier. I also would recommend to you that you still take the healthy skin of the other nasal wing or the other cheek as a control to know what the structures of the skin look like in this exact same spot. Now let's move on to the summary. Here you have the typical BCC criteria on the right side and the typical squamous carcinoma criteria in the middle and the typical actinic keratosis criteria on the left. And I think with this table you are already doing pretty well. If you keep this in mind it will help you a lot in diagnosing BCCs and actinic keratosis. And with this slide we have come to an end and I say thank you very very much for your time and of course your attention so bye-bye see you next time!

Bézacer carcinoma

OCT imaging

diagnosis criteria

dermoscopy

differential diagnoses