Hello, everybody. Are you ready for this lecture? Now we will talk about the role of ultrasound in benign cutaneous tumors and pseudo tumors. This is my disclosure. Hello, my name is Fernando Pacemea-Ferradante, and I'm the coordinator of the Dermatologic Ultrasound Unit at Hospital Puerta de Hierro, Madrid, Málaga. In our department, dermatologic ultrasound is a key complementary test in the management of benign skin lesions, both vascular and non-vascular. In the case of vascular lesions, differentiation of vascular tumors from vascular malformations can be accomplished with dermatologic ultrasound in order to start correct treatment. For non-vascular lesions, dermatologic ultrasound helps to differentiate benign or malignant lesions. Because of this, dermatologic ultrasound is a first-order diagnostic tool in any dermatologic departments. Well, you listened to the opinion of Dr. Fernando Alfajeme in the previous slide. We are very happy to hear it. And now I am sharing with you what we are talking about. We will talk about common dermatologic tumors and cellular tumors, how to differentiate an ultrasound in meningiomas and vascular malformations, and some less common tumors. Here you can see several cutaneous lesions that look like some bumps and lumps, but they could have a similar origin. So we are going to find out how to discriminate the type of lesion that we are seeing in the surface with ultrasound, of course. For assessing the nature of lesion, we need to know an ultrasound several features. First, we need to know if the structure is cystic or solid. The structure will be cystic if it is anechoic or hypoechoic with posterior acoustic enhancement or reinforcement, if the lesion is partially or totally compressible and without internal vessels. The lesion will be solid if, for example, it is hypoechoic or hypoechoic and the structure is non-compressible. It could show or not internal vascularity. Another important characteristic that we need to describe is the shape. It could be round, oval, band-like, or sac-like, according to the nature. We need to know the borders, if they are well or ill-defined, if this structure generates some special artifacts. You have heard in the previous class several types of artifacts, and, of course, the location, the layer where this lesion is. Here you can see an ultrasonographic algorithm for discriminating common dermatologic lesions. So I will show you how this process can be, let's say, more easy. So let's take this path. Let's say you find an anechoic or hypoechoic structure with posterior acoustic enhancement, which is partially or totally compressible and without internal vessels. So you are seeing a cystic structure. And let's say this cystic structure is not located located on the scalp or in the intergluteal region. So the first thing that you have to think it's an epidermal cyst. Epidermal cysts could be well-defined or ill-defined according to the presence of rupture within the cyst. So we will find out how to discriminate more. This is an intact epidermal cyst, or so-called inclusion cyst. You can see the cutaneous lesion, and this cystic structure contains keratin and is produced by remnants of epidermal components in the dermis or subcutaneous tissue. An ultrasound, it will look like an oval, round-shaped structure, anechoic or hypoechoic, with posterior acoustic enhancement, as you see here. And look at the layers here, the hypoechoic layers within this cystic structure that corresponds to layers of keratin. In this case, this epidermal cyst was very close to the facial artery. This is not something that could be irrelevant to say. This is something important in terms of surgical planning. Another intact epidermal cyst here, you can see the cyst as hypoechoic, located in the dermis and the subcutaneous tissue, and also very close to another important vascular structure, in this case, the angular artery. At 70 MHz, you can discriminate the capsule of the cyst. And that is very important if, for example, the cyst is ruptured and you want to know if there are remnants of the capsule. But of course, you need a higher frequency ultrasound machine. In this case, the epidermal cyst was ruptured. So you can see a partial rupture as a loss of definition in parts of this structure located in the dermis and subcutaneous tissue, and an hypervascularity in the periphery of the cyst. This is a totally ruptured epidermal cyst, and you can notice that the cyst now looks completely the oval shape or all round shape, and now it's completely irregular. It's still located in the dermis and subcutaneous tissue, but you can notice the posterior acoustic enhancement artifact underneath this structure. That is a very important sign for discriminating a ruptured cyst, and also the hypervascularity in the periphery of this structure. This is another totally ruptured epidermal cyst. You can see the cutaneous lesion and an ultrasound. You can notice the ill-defined hypoechoic structure located in the dermis and subcutaneous tissue with the posterior acoustic reinforcement artifact, and also the hypervascularity in the periphery of this structure, which is very clear on color doppler. At 70 MHz, you can notice the remnants of the capsule here was an hypoechoic band in the periphery of this structure. So epidermal cyst looks very different if the lesion is intact or ruptured, as you can see, but one sign that really helps us is to find this posterior acoustic enhancement artifact underneath the lesion. So let's go now to a cystic lesion located on the scalp. So we have to think about a tricholemal cyst. Tricholemal cyst also can become inflamed and partially or totally ruptured. So this is a tricholemal cyst. This is a cyst derived from the external sheath of the hair follicle without the granule layer, which is different from the epidermal cyst. The most common location is the scalp, and here you can see one on ultrasound that corresponds with the cutaneous visible lesion, and you can notice the oval-shaped hypoechoic structure located in the dermis and subcutaneous tissue with a posterior acoustic enhancement underneath. Notice the hypervascularity in the periphery of the cyst due to the inflammation. Now, we suppose we are seeing an anechoic or hypoechoic structure with this posterior acoustic enhancement, but located in the intergluteal region, and this structure presents linear hypoechoic areas and echoes that suggest fragments of hair tracts. So we have to think about a pilonidal cyst. This is a pilonidal cyst. This is not really a cyst. This is a pseudocyst or cavity, usually in the lumbosacral region that contains a nest of hair tracts and keratin. These pilonidal cystic structures could appear as sac-like or band-like very long structures, and they usually contain these linear hypoechoic structures that correspond to fragments of hair tracts. Notice the hypervascularity in the periphery of this lesion that is located in the dermis and subcutaneous tissue. In the old times, these pilonidal cysts were thought to be due to the embedding of the hair tracts in the skin, but now we know that these fragments of hair tracts or hair shafts, as you wish to call it, they are produced ectopically in the dermis and subcutaneous tissue due to ruptures of the hair follicles and a seed of stem cells. Usually these fragments of hair tracts are very prominent in pilonidal cyst, and these lesions are connected to the dilated base of the original hair follicles. These characteristics are very similar to hydrodenitis superlativa, and it has been proposed that pilonidal cysts are really localized forms of hydrodenitis superlativa because they present similar findings, although of course localized. Now we are going to move to a solid structure. So let's see a novel round-shaped structure with an hypoechoic rim and an hypoechoic center that contain focal hypoechoic deposits of calcium. In that case, we have to think about epilometrixoma. Well, this is an epilometrixoma ultrasound, and you can see the clinical lesion on the left and then the lesion on the right, an ultrasound, and you can notice that this structure presents like a target type of appearance with an hypoechoic rim and heterogeneous and hypoechoic center that present these dots, hypoechoic dots that show posterior acoustic shadowing artifact that corresponds with the calcium deposits in the tumor. Epilometrixomas are usually located in the dermis, subcutaneous tissue, and oncolodoppler or power doppler, they may show hypervascularity in the periphery or within this tumor. Some epilometrixomas could have a very bad location like this one, located in the neck, so very close to the jugular vein, and this is another patient with epilometrixoma. You can see the clinical lesion and then an ultrasound, this target type of structure with an hypoechoic rim and heterogeneous center with these hypoechoic dots that correspond to the calcium deposits and hypervascularity in the periphery or within this lesion. At 70 megahertz, this is ultra high frequency, we can see better the calcium deposits as you can see here and the hypervascularity, but the key here is to find the calcium because the calcium is the pathognomonic sign of epilometrixomas, but some of them may present a low degree of calcification and on the other end we have other tumors that are completely calcified, but we have to look for these hypoechoic dots with this tiny posterior acoustic shadowing artifact. This is a patient with a lesion that was treated because of hemangioma and due to the lack of results, the patient was sent to an ultrasound. And look at the lesion, it's a target type of lesion with an hypoechoic border and heterogeneous center with these hypoechoic spots, and look at the vascularity within the lesion. Notice that the lesion is well defined, round shape, and of course is located in the dermis and subcutaneous tissue, and you can see here the tumor at the surgery. Importantly, there is a cystic or bullious variant of epilometrixoma that occurs due to hemorrhage within the tumor, so you can see an anechoic space between the capsule and the center, sometimes with some septa, and this could be very tricky from the clinical point of view because it doesn't palpate as a hard nodule, it looks very soft, but in the ultrasound examination, you can find out these hypoechoic dots that correspond to the calcium deposits in the nodule of the tumor. And you can see here a case, look at the vascularity within the lesion, and look at the space. Usually this space, this anechoic space, presents aromatic components, and you can see here the histologic lesion. Then we move to another solid tumor, but oval shape and fully hypoechoic, hyperechoic, and in this case, we have to think about an angiolipoma. And look at this lesion here in the infraauricular region. This was caused because of an angiolipoma, which is a benign tumor that contains mature adipose cells mixed with capillary vessels, and this tumor can be oval or round in shape, but it tends to follow the axis of the skin layers, as you can see here in these ultrasound images. Sometimes you can find some vessels, usually low flow vascularity, but sometimes you don't find it, and this hypoechoic structure is due to the capillary component. What happens if we find a solid structure, oval shape, hypoechoic with hypoechoic septa? Then we have to think about a fibrolipoma. This is the most common benign soft tissue tumor, and this tumor contains mature adipose cells with fibrous component. This benign tumor tends to follow the axis of the skin layers, but sometimes it can present lovulated borders or it may adhere to the dermis and simulate another type of lesion. Look here, the tumor, you have the clinical image with the lump, and then you have the fibrolipoma in the subcutaneous tissue, oval shape, hypoechoic, and with some hypoechoic fibro septa, which is normal in the fat, in the fatty tissue, right? And look the few vessels within the lesion, so this is a benign structure. We have to think about malignancy when these lesions tend to measure more than five centimeters, they are heterogeneous, or they present a very high vascularity. I'm going to talk a few words about this special type of lipoma, it's a subgallial lipoma located underneath the muscle and on top of the bony margin of the skull, because this tumor can produce some problems, especially because of the locations, because if you are going to plan a surgery and maybe you will not find this tumor because of the deep location. So in that case, ultrasound can be helpful because you can exactly know that the lipoma is underneath the muscle. So be careful with this location. What about a van-like structure that could be hypoechoic and that connects the skin with the bony margin of the mandible or the mandible? In that case, we have to think about an odontogenic fistula. An odontogenic fistula could be very tricky from the clinical point of view because it could cause a lump and somebody that is not aware of this could think about an epidermal cyst or another type of lesion. And in this case, ultrasound is very clear because it can show the fistula's tract that is connecting the dermal region with the bony margin of the upper maxilla. And even you can notice here an interruption in the bony margin because there is an erosion that is very close to the dental area. Of course, there is hypervascularity in the periphery of this lesion. So, this is the first slide that I show you with the different lamps, and now you realize that there are ways to discriminate these different types of lesion and ultrasound, and that is a very helpful method for the discrimination. A few words about hemangiomas and vascular malformations. Of course, these vascular anomalies are very common, and it is important that you can discriminate between them with ultrasound. We know that these entities present different pathophysiology, evolution, prognosis, and treatment, but they could be clinically similar. Hemangiomas we know that, and I'm talking about, of course, infantile hemangiomas, are the most common tumors of infancy, and they contain two endothelial proliferations. We know that these tumors present different phases, and we can discriminate these phases on ultrasound, because in the proliferative phase, we know that this mass will be predominantly hypoechoic and highly hypervascular, and during the partial regression phase, we know that the tumor changes the echogenicity and becomes mixed with some hypoechoic and hyperechoic areas, and present an hypervascularity in a lower degree in comparison with the proliferative phase. And then we have the total regression phase, where we can see mostly hyperechoic structure, that is hypovascular, it can present a few vessels, but mostly this is due because of the replacement of the tumor for fibrous deposed tissue. The key point here is to find a mass appearance. This is very important for the differentiation between hemangioma of infancy, and you can notice here the ultrasonographic appearance of infantile hemangioma during the different phases. So, in gray scale on the left, you can see the hypoechoic nature of the tumor in proliferative phase, and then how the tumor changes to hypoechoic during the regression phase. On the right, you can notice the difference in the hypervascularity between the proliferative and the total involution phase. So you can go from a very high hypervascular tumor to a very low hypovascular lesion. This is a case of an hemangioma of infancy in proliferative phase. You have the clinical lesion on your left in the tip of the nose, and then you have the ultrasound images and transverse view of the tip of the nose, and you can notice very clearly the hypoechoic oval shape structure in the subcutaneous tissue with a very high vascularity on color doubler. This tumor involves the left nasal alar cartilage, and that is very important information if you want to plan surgery when the child becomes older. And this is the same tumor on power doubler and also in echo angio, and the detection of vascularity is very evident on color doubler, tosan, and all the modes. Also, we remember that we have to detect the type of vessels, and these tumors usually present arterial and venous flow and some arteriovenous shunts. You can see the arterial flow with these systolic and diastolic phases, and then the monophasic venous flow on your right. Sometimes these tumors compensate very high velocity, very close to the velocity of very important vessels, such as the carotid artery. This is another hemangioma of infancy, in this case, a deeper lesion that involves the parotid glands, and this very evident, the hypervascularity within the tumor. Now we are moving to an hemangioma of infancy in partial regression phase, and you can see that the lesion is really mixed in ecogenicity, is involving the dermis and the subcutaneous tissue, with, let's say, an intermediate degree of hypervascularity. And this is an hemangioma of infancy in total regression phase, and you can see an hyper-echoic lesion in the subcutaneous tissue that extends to the dermis, and with few vessels if you compare with the proliferative and the partial regression phase. What is the main role of ultrasound in hemangiomas of infancy? Well, the detection of the involvement of deeper layers, and of course, the knowledge of the phase of the hemangioma, and this could help you to monitor the evolution and adjust the treatment. If you are going to, let's say, suspend propranolol, increase or decrease the dosage, that could be a very good information to know. A few words about vascular malformations, because they could be clinically similar to hemangiomas of infancy in some cases. So we know that these are, of course, errors of morphogenesis, not real tumors, and they are composed of disproportionately high number of channels, of vessels, and they grow in a proportionate way over time. They could be classified in high flow or low flow. High flow are the arterial and arteriovenous, and in low flow we have the venous, lymphatic, and capillary. Can we discriminate these types on ultrasound? Of course, yes. I'm going to show you this high flow arterial vascular malformation, and you can notice the clinical, very subtle clinical lesion in the thigh, and then an ultrasound. You can notice this tubular anechoic vascular structure in the subcutaneous tissue with a very high vascularity that is really turbulent. That's why you see this very heterogeneous map of colors within the lesion. This is with the anecho-angio that you can discriminate better the shape and the nature of the vessels, and then look at the velocity of this arterial blood flow, which is more than 40 centimeters per second, as a reference, normally in the skin you don't find higher than 15 centimeters per second velocity. So that is a high velocity. And this is a case of a low flow venous vascular malformation. You can see the lesion on the skin, and then you can notice the tubular anechoic structures in the subcutaneous tissue in the right images. Of course, there is a very low velocity blood flow, and if you compress these structures, you can see the reflux of the flow. If you take your spectral curve analysis, you can notice the monophasic flow typically seen in venous structures. And this is a low flow lymphatic vascular malformation, and you can notice a very subtle alteration in the color of the skin, but on the right side you can see this lacunar and tubular anechoic areas in the subcutaneous tissue without any detectable blood flow within these structures, and this is a lymphatic vascular malformation. Low flow lymphatic vascular malformations can be very lacunar sometimes, and they could be a little bit irregular, and they do not present blood flow, or at least detectable blood flow on the spectral curve analysis. And this is a capillary malformation, a low flow capillary malformation, and we don't catch tubular structures here. We just see some alterations in the ecogenicity, in this case an hypoecogenicity of the dermis and an hypoecogenicity of the subcutaneous tissue without any blood flow detectable on the color Doppler ultrasound. So the main role of ultrasound in vascular malformation is to identify the type and extent of the vascular malformation. This could help you to plant and guide percutaneous procedure sites such as sclerotherapy and also monitor noninvasive treatments such as laces, for example. What about less common tumors? And this is the last part. I'm going to talk about the nodular dermatofibroma. This is a fibrous tumor, of course, and this is the most typical presentation of the nodular type that appears like an hypoecoic dermal structure, usually ill-defined with few vessels in the periphery. Sometimes it presents this hypoecoic central, a little bit oval shape or round shape structure in the middle of the lesion, but usually with low vascularity. This is another type of dermatofibroma. And another characteristic of dermatofibroma is that they usually distort the hair follicles, like in this case. So if you are looking an ill-defined hypoecoic heterogeneous structure with distortion of the hair follicles and with hypovascularity, or let's say intermediate degree of vascularity, we have to think about the dermatofibroma. When we think about the dermatofibrosarcoma, well, the dermatofibrosarcoma usually extend to the subcutaneous tissue and present pseudopods, hypoecoic pseudopods, and much higher hypoecoic pseudopods. This is a very interesting benign tumor. It is called apocrine nodular hydradenoma. It is a tumor derived from the sweat glands. And what is interesting is that here the clinical and dermatoscopic examinations present, according to the publications, a high rate of errors. This is a mixed tumor with a solid and cystic component. So you will see different ecogenicities within the lesion, normally located in the dermis and subcutaneous tissue. And you can notice on the images on the right, this hypoecoic and anechoic area with some septa and some vascularity in the hypoecoic areas. This is another apocrine nodular hydradenoma. You can notice that the lesion is clinically different from the lesion that you saw before. And you can notice the mixed structure with hypoecoic and anechoic areas with some fluid fluid levels because it has some ceramatic components within the tumor that generate this disappearance. And of course, with some hypervascularity in there. One very cool sign and ultrasound in this apocrine nodular hydradenoma is the snow falling. And these are echoes that are moving with the sound. And you can see going from the surface to the bottom of the lesion. Sometimes you have to increase the gain to detect them, but they are very, very common in these tumors. So after this very cool tumor, we can conclude and mention that ultrasound can support a differential diagnosis of common dermatologic tumors and pseudotumors and vascular anomalies. So see you in the next class, and I'm very happy that you're attending this course.

dermatologic ultrasound

benign cutaneous tumors

vascular lesions

non-vascular lesions

diagnosis

ultrasound features

tumor differentiation

ultrasound

cutaneous tumors

epidermal cysts

treatment planning