 All right, so we're going back to Edinburgh Castle. So the other thing you don't realize is you have to sit through my travel sides with these talks. I've got a captive audience. All right, so there's the line going to Edinburgh Castle. And the nice thing is, as you go inside, you can pretty much go around every, of course, there's a line into everything, but you can pretty much go all the way through the castle. So that's kind of like the main heart of the castle. And on the top, you can imagine they had archers up there to try to defend it. And it's still the United Kingdom flag, although Scotland did have a referendum to secede from Great Britain, but it was voted down barely. And this is the chapel. There's a chapel on top here. And then this is the nice thing. These are the views. So this is the old city of Edinburgh. Looking at it, Edinburgh is right on an inlet from the, now, Edinburgh is on the far east side of Scotland. And so it's kind of the sea between Scotland and Europe there, but there's an inlet to the sea. And so Edinburgh actually has a port right there. As usual, it's gray. It's like gray there for 300 days of the year. It's kind of the opposite of Utah. So it's the usual gray that you see. All right, so we're going to talk about orbit a little bit. And we're talking about orbit. The first thing that we want to do is you always want to make sure that you know what the definition of the orbit is. And I thought this was a pointer. Well, unfortunately, the pointer is not pointing. I don't really see anything coming out of here. Sorry. So whenever we're talking about the orbit, you want to make sure that you understand what constitutes the orbit. And the first thing that when you're looking at the orbital path, you want to make sure that you understand what the bones are of the orbit. So always the first question we ask is, what are the orbital bones? So Julia, tell me what the orbital bones are. OK, that's seven, right? Well, lesser and greater are the same thing. So they just count as one. They just count as one. OK, the Palatine is what people always forget. So I didn't get you on that one. Usually it's the Palatine that people just completely forget about. But when you look at the orbit now, Maurice, the orbit is divided into three main areas. What are the three areas anatomically that we divide the orbit into? Well, that's where the lids, how about the orbit itself? OK, good. Yep. And again, one people forget about. Well, you can call periosteal, subperiosteal is a potential orbit. So when you divide the orbit, intraconal, what does intraconal mean? Inside the muscle cone. Exactly. So when you look at the muscles, the muscles have an intramuscular septum and they form a cone coming out from the apex of the orbit out to where the muscles insert. And so intraconal and then extraconal is what we really think about as the orbit. And then you could sometimes have where the periosteum is. There's a subperiosteal area there that, again, can be a potential space. So when we look at it here, we're looking at it in a little bit of a sagittal cut. Brian, tell me some of the structures that are intraconal, what are the most important structures intraconally? Good. Those are kind of the two important ones. Those are main ones. And we talked about optic nerve tumors last time. And so you can get tumors within the optic nerve intraconally. And then, of course, as you said, the ophthalmic artery goes in and then the various branches come out from the ophthalmic artery intraconally. Extraconally, there's a lot of fat and some septae and not a whole lot else going on extraconally. So we kind of look at it in an MRI. And again, you can see where the muscles are, denoting the intraconal from the extraconal space. What are we looking at here, I think? And what kind of gland is the lacrimal gland? Ecring gland. OK, so it's an ecring gland. It's a secretory gland, similar to sweat glands. And we kind of forget that the ecring gland is part of the orbit. Now, when we divide the lacrimal gland, what are the two major areas we divide it into? And what divides those two? Exactly. So the orbital lobe is what we think of as the lacrimal gland. But then when the orbital septum comes down anterior to that, there's a palpebral lobe, a small lobe of the lacrimal gland. And when you're inside the orbit, going ahead and trying to remove tumors and remove tissue, you can often disrupt that. And so when you disrupt that, you can lose some of your basal tear secretions and cause significant dry eyes. So see, the pattern of the lacrimal gland, it's like other ecring glands. It's like an assener pattern. So it's got a round gland that secretes into the center. And then it's got these little myoepithelial cells. And I wish I had a pointer to kind of surround the glands and have the little contractile elements that squeeze out the lacrimal secretion, if you will. So the problem with orbit is, when we look at the orbit, you can't often see anything from the outside. And that's the problem is, is we often don't know what's going on. We have to kind of infer it from other things. And so you thought you were going to get reprieved, because it's your first day. But at least looking at this picture, you can tell me which eye is abnormal. And how would you tell that? You don't even have to read to know this one. By looking at the two-eyed state of the patient, if there's a left eye, that looks like there's some discharge there, so maybe you have normality there. OK, now remember, what are we talking about today? What part of the orbit? Exactly. So look at the light reflex that's sitting on there. How is that light reflex different? Yeah, and not only that, but the left eye is lower. The light reflex is higher in the pupil. So it's as if something's above that left eye and kind of pushing it down and also pushing it in a little bit. So since we were just talking about this particular structure when we looked at it, we're looking at a scan here. Julia, what are we looking at here? All right, so we've got this lesion. It's kind of superior in temporal, which is where the lacrimal gland sits in its coin shape. Is that important? So what are the most common lesions that can affect the lacrimal gland? So in the olden days, like when I was a resident, we were taught the 50-50 rule, and that was that 50% of all lacrimal lesions were intrinsic tumors of the lacrimal gland, and then 50% of those were what we call these benign mixed or tumors that are arising from the lacrimal gland. But since people have really looked at lacrimal lesions and the shield's at Al, both of the shield's is plural, they looked at all of their lacrimal lesions that they had looked at at wills, and they found that about 80% of them are actually lymphoid in origin. And so the old 50-50 rule got chucked out. So really the most common lesion affecting the lacrimal gland is lymphoid, be it either benign lymphoid hyperplasia or a decryoadnitis or a lymphoma. But when you're looking at the actual epithelial lesions of the lacrimal gland, again, the 50-50 rule takes effect. So half of them are going to be the so-called benign mixed or pleomorphic adenomas, and these tend to have a round coin lesion when you look at them. And so when they grow, they don't have an actual capsule around them, but they do have a pseudo capsule. So they kind of grow slowly and push out and push the connective tissue forming a pseudo capsule. So Rhys, what are the cellular components that make this up? It's still a glandular structure, she's telling me. OK, so this is one where the name describes it, which is really easy, because benign mixed. So mixed, meaning it's a mixture of proliferation of the glandular elements, but also those myoepithelial elements that we talked about. So you'll see kind of elongated, proliferative glandular elements, but in between them, you'll see the cellular proliferation of the myoepithelial cells that are there. So it's both of them. And they call it benign mixed, because it tends to be relatively benign, meaning that it doesn't send fingers out all over, it doesn't metastasize, it slowly grows with one caveat. The but is if you go in there to remove this and you just biopsy and you leave more in there and it kind of spills out in the orbit, these cells get ticked off at that and they start to become more nasty and grow a little bit more aggressive. So this is the one lesion where you definitely want to do an excisional biopsy. You want to remove it whole. You don't want to remove part of this behind. And here's a close-up. You can see the proliferation of the cord-like glandular elements that are in there. Now, sometimes if you take this out, you don't take it out completely. You just can't get it all out. It can grow back and it can actually start to change from what we call a benign mix to a malignant mix. Now, fortunately, malignant mix does not as common. And so this malignant mix, you start to look at it. They still got proliferation of both cellular elements, but they start to look atypical. They start to look dysplastic. So that's a malignant mix. And that's if you don't get the benign mixed out completely. And I know it's hard for you guys to see. I should have probably taken a higher power of this, but there are a little nucleoli in there. There's a little chromatone in there. And so these cells have become much more active and these can be a more aggressive tumor once they become a malignant mix. There's a close-up. That's a better picture. You can see the little nucleoli that are in there. You can see that these are just a little bit more aggressive. So Dr. Namas, that's the difference, then? It's just the activity of this. It's the activity. And also, once you've violated that capsule, you lose that pseudo-encapsulated look. So they start to grow more diffusely. All right, Brian, since you are up anyway, a little bit more obvious which eye is involved here when we look at it. Yeah, so the left eye, it looks like there's again some hypoglobus, inferior squaralum show. The eyelid has some probably mechanical ptosis and then some fullness of the left upper eyelid. All right, so you'd be, again, concerned of about kind of a superior temporal lesion in that area. And sure enough, when you do it, this is a coronal scan now. And sure enough, you can see that lesion up superior temporally. Now, this is a little bit different lesion. What is this one? That's the adenoid cystic. OK, so on this particular picture, this kind of denotes one of the propensities for this lesion to grow. What are we seeing on this picture where this lesion is growing? Exactly, it's going into the bone. And so these tend to be much more aggressive tumors. The problem is this is one of those tumors that's been described as, quote, disarmingly benign. And I'd said most times when we look at tumors, we can tell how aggressive they're going to be by how they look when you look at them. But this is one of the tumors. You look at the cellularity to it, and it looks pretty benign. And these can actually be very aggressive tumors. And so when you look at these, sometimes they can have a Swiss cheese or a cribriform pattern to them, where you see this little Swiss cheese effect. And there's a close up. But there's one particular subtype of these tumors that are alarming. And this is the one you'll need to know for boards. What does this denote? Exactly, basaloid or basilar type of proliferation. And when people have looked at these tumors, they've wanted to say, OK, these are really bad actors. These can metastasize. They can spread locally. But when they look at the subtype, it's this particular subtype that's the really nasty actor. And if you look at it, it almost kind of looks like a basal cell. And remember how basal cell, you had these nodules of really packed-in tumor cells. And so you can see here, it hasn't taken over the whole acromole gland, just part of it. And so this basaloid variety is the one that's a particularly bad actor. And these can actually metastasize. People can die from these. And so these are a particularly nasty one that you don't want to miss. All right, Eileen, we're looking at this patient here. So what would you be concerned about here? So that's always in your differential when you see that as a preceptal cellulitis, or what other things can look like this? And also what used to be called pseudotumor. Now they call that idiopathic orbital inflammation. That can be anterior, too, and look like this. But the interesting thing about this is if you look, it's kind of red and swollen. But you maybe have a little bit of redness underneath, but not the really hot look that you would see usually in a preceptal cellulitis. And when you look at this, you can see in this coronal view, what do you call that when you see it kind of going around and plastering itself around ocular structures? Exactly, so remember the coin lesion tended to grow in one area and then push against the eye? This tends to be really diffuse and mold around. Did you guys ever have silly putty when you were kids? Did that still exist? You know, silly putty molds around everything. Lesions like this tend to be lymphoid in origin, and they tend to mold around the ocular structures. And so don't forget what we said, the most common entity that affects the lacrimal gland is not so much the tumors that we had talked about, but this entity, and what do we see here? Yeah, so when you look at a lymphoma, it almost looks like someone took just a handful of lymphocytes and just smeared them across the slide. So there's just this diffuse infiltrator, these small blue lymphocytes. So don't forget lymphoma, but also you can have dachryoidinitis, you know, a benign proliferation affecting that. And here is an immunoperoxidase stain, and that's a way we can sometimes tell lymphoma from lymphoid proliferation as you look and see for clonality, and this particular lesion turned out to be a pure B-cell capa. So lymphomas can affect the lacrimal gland. All right, Julia, this is a familiar picture from last week, what are we showing here? And what are the carotid folds usually denote? All right, it's an intraconal mass. What's the most common cause for carotid folds? Exactly, so hyperopia with a flat posterior surface of the eye, so don't always jump in for tumors. And so if you're ever on boards, you wanna say exactly that answer, you wanna say, well, this is indicative, it could be indicative of a mass intraconally behind you, however, you know, when you look at series of these, the most common reason for this is just a hyperopic flat eye. So intraconal lesion, so we talked last week about some of the tumors that can affect the optic nerve, meningiomas, gliomas, even schwannomas, but there's another lesion that can affect that. Let's say this is a 28-year-old, vague symptoms of fullness around the eye, maybe a little bit of pain and you saw that, carotid folds, and then you do this scan and you see this lesion. What would you be concerned about here? Okay, so when you see this grape-like lesion intraconally, kind of slowly growing, you may have some subtle proptosis, some subtle symptoms, and so the most common lesion that affects that is a cavernous hemangioma. So when you look at these, again, just like the benign mix tumors of lachmoglobin, these tend to have a pseudocapsule around them. It's not a true capsule, but they grow really slowly and they've got this capsule surrounding them, so the nice thing is when you remove these, they tend to just come right out. It's like you go in there and you move the tissue around and then you pop out, just like pulling a grape out of there. And the other thing is, is they have a very, very slow turnover of blood in there, so these don't bleed. These aren't like the cavernous, not like the capillary hemangiomas, I'm sorry, the lids that bleed like crazy. These usually don't bleed. And here's low power. You can see the pseudocapsule around it down here, and then you see it's characterized cavernous, big, you know, big vascular spaces with little fibrous septae between them, and how can we tell that the blood flow is slow through these? Yeah, so what is that that's layering? Yeah, so actually that's just serum separating from red blood cells, and so this is your, you know, hematocrit, you know, tube that you do. And so you can see the hematocrit, this guy's a, you know, a blood doper. I mean, that hematocrit's like 60, they're easy, so if you look at it when it's here. So you see the actual, the flow is so slow that the serum separates off on the top and the red blood cells go to the bottom. So these tend to be benign, but because they're in that closed, intraconal space, they can grow when they can cause problems. And so you do want to get them out of there before they cause problems, because there's some kind of minorly important structures next to them like the optic nerve, you know, so you don't want to let them grow too big. All right, what are we seeing right here, Rhys? So there's some, yeah, when you have sclerosis, it's a sign that maybe that eye's coming out toward you. So, you know, again, first thing you want to do is say, gee, which eye's abnormal? And then what do we see in them? Because you really can't see the ore, but that's a nice thing about ophthalmology. It's a visual science. We can see what's going on in there, but orbit, you can't. And so you do have to jump to a scan, but Boopy will really pound you guys. You want to, you know, get as much history and as much physical exam as you can before you jump to that scan and try to figure out what you're looking for. And so this particular patient had a biopsy and this is what it looked like. So at low power, there's a certain pattern there I want you to look at. Yeah, it's kind of called a stag horn. You know, stag is like a deer and horn, you know, it's like deer horns. It's a nice stag horn looks for, for those of you, you know, bambi killers out there, you know, this is what you're shooting at with your high powered rifle, you know. All right, so this is a vascular channel shaped like a stag horn, but if you look carefully, look, there's vascular channels all over the place in here, but there's a whole bunch of cells in between. What do you think this lesion could be? Now look up from that book, da, da, da, da, da, da, da. No, it's not, it's just working, you know. Okay. Would this one be like a hemangio perisatoma? Exactly, so this is a hemangio perisatoma. So not only a proliferation of vessels, but also the parasites around the vessels. So hemangio perisatoma, it's characterized by these classic stag horn appearance. The secret number one that you get. You can sometimes get stag horns in. Exactly, you can have big stag horns in the lymph angioma, so hold that thought. We'll get there, but yeah, you can. So it doesn't necessarily mean it, but the key that tells you it's hemangio perisatoma is it's packed with cells around those little stag horns. And so you can see each one of these little channels. Now this is a higher power. Look, there's a whole bunch of blood vessels. Every one of these blood vessels is lined by these pump capillary channels, but in between you've got this proliferation of these perisites. So hemangio perisatoma. And this is just a closeup showing you these mini stag horn spaces, but a lot of vascular channels and blood. Now the thing with these hemangio perisatomas is we also try to classify them on how atypical they look. And so you can have benign, more of an intermediate, and then a more malignant variety. And if you look right here, look at the parasite cells. You see how they've got nucleoline in them? They've got clump chromatin. And so we really look hard pathologically and we say, okay, is this going to be aggressive or not? And is the pathology worrisome? And yet after all that, when people who see a lot of these have looked and said, okay, does the histopathological findings match with how aggressive they are? The answer is no. It's weird. There's some that look benign, that behave really aggressively. There's some that look more malignant and behave not so aggressively. So unfortunately that's one of the times where again this cellular makeup of the tumor is not really prognostic. The problem with these is they are not encapsulated. They're very hard to remove. And we've got a couple of patients that even started when Rick Anderson used to be here that then Bupi's taken over that. They've gone back in three and four times and each time they do, it gets a little bit more aggressive and you know, can cause a little bit more damage. So these are, as Bupi would say, a real bugbear. Bugbear, take this out. So chap comes in with one of these, bugbear. So these are really difficult sometimes. And so remember, they can be more benign or they can be mixture or they can be more malignant looking. And here's one of the more malignant looking ones. Again, you can see how there's some pleomorphism, different sizes and shapes of the cells. Clumped chromatin, you know, some nucleoli in there. Now there's one special stain we can do that really helps us out and bonus points for knowing what this stain is. Reticulum stain, exactly. And what does that mean? Okay, technically that is a true answer, yes. I said it with conviction too. Yeah, you said it with conviction, very good. So basically you remember the pericytes are kind of the support cells around vessels. And so they do have this supporting network of connective tissue. And so when you do a reticulum stain, which is a silver stain. And so it'll stay in this reticular, you know, network here, black or silvery. And so you'll see this extensive reticular network around. So this is really helpful when you're looking at lesions like this to do the retic stain. All right, Brian, what are we seeing here? Exactly, so it's kind of multiloculated. And if you look at it, you see some, you know, it's not really uniform in terms of how it's showing up on the CT scan. And you can see there's areas where it looks lighter staining and darker staining and it's septated. And you've got a lot of proptosis here going on. So how do you think this patient is? Exactly, so this is like a 10-year-old kid. And this waxes and wanes. They'll get proptosis, then it settles down, then more proptosis, then it settles down. And so speaking of giant stag horns, you know, what is this lesion or what is this entity? This is a lymph angioma. And so people call it that because they think that these big spaces almost look like lymphatic channels rather than vessels. And so when you look at these large, you know, channels and they're lined by a flattened, kind of spindly and complete endothelial lining, much like a lymphatic channel would be. And so this is a lymph angioma. And then what are these down here? Lymphocytes. And so you really do get patches of lymphocytes around these channels. And when the kids get a viral infection, especially an upper respiratory or nasal viral infection, these can grow rapidly. And so these lymphocytes will proliferate, the cysts will get really big. The problem is when you're treating these, again, these are not encapsulated. And so you can cause more damage trying to take these things out. And sometimes when they'll get an explosive proptosis and it's due to a big cyst, people will actually go in with CT or ultrasound guided needles and actually drain the cysts without having to go in and do surgery. And so if you can get them through that acute period, these will often settle down again. And you can see a close-up of one. Now what has happened here, Eileen? Exactly. Let's say the resident didn't do the surgery here. And this is what it really looked like before they took it out. Yeah, so every once in a while, you get an explosive proptosis because you can get one of the small blood vessels that surround those big stancords will bleed into it. And then when that blood sits there for a while, it'll start to break down. And instead of being nice and red, it'll turn that brown chocolatey. And so they call these chocolate cysts. So when you get bleeding into these cysts, you can get an explosive proptosis. And then you see that eventually those blood cells will break down and they call it a chocolate cyst. There's a close-up. You can see the blood within this, the big staghorn spaces. But then again, you see these lymphocyte clump, lymphocyte groupings that are there kind of around the lesion. So lymph angioma. There's a close-up of the lymphocytes. Okay. God, we're down to, what is it? Is it, if I got bad breath this morning or something? It's like, geez, we're down to like two of you guys? I mean, I know it's, it was Valentine's Day, but gosh, Brian again, what are we seeing here? Is this a picture from? This was when I first came here as an attending. Yep. So, well, I'll tell you. So it's a horrible proptosis and hyperglobus on the right and the eyes deviated down. I would guess that it happened pretty quickly to get to the back form. It happened really quickly. And this was the actual scan on this kid. Because it's like we're a third world, you know, some slow room, I could do it. But here, yeah. This was really rapid. So the story is mom brings the kid in to primaries in explosive proptosis. We do a biopsy. We say it's a tumor. We tell the mom she needs chemotherapy. They start to give the kid chemo. The lesion starts to respond and the kid's hair starts to fall on. She gets sick, so mom immediately takes the kid and goes to Mexico for coffee enemas and leitral treatment. You guys don't remember leitral. It's the stuff that cured tumors. And so you'd go to these clinics in Mexico, Miracle Cure, and what they would do is they'd give you coffee enemas because the enema would remove bad tumors from your body. And so that would help to cure you. And then they'd give you leitral. And at the same time, they'd also give you something else with the leitral and this cocktail, i.e. steroid. And then the patients would say, wow, I feel better. And then they'd come back and tell all their friends, I went to Mexico. Instead of those bad old US doctors, you know, there's a conspiracy. Doctors just want to make money and control everything. Those good Mexican doctors treated me. And then they would come back feeling good afterwards. And then they'd keep taking the medicine and then they would die from complications, either of the tumor explosively re-growing or the steroids. And so basically dad, who was divorced from mom, hired a private detective, tracked mom down to this clinic in Mexico. Dad flew down there and kidnapped the kid and brought her back. By then the tumor had grown so much that the kid ended up having an ex-generation and her life was in jeopardy. So interesting, interesting story. Of course they were from Utah County, the home of homeopathy and, you know, magic cures. All right, so unfortunately my fellows took these beautiful pictures once for orbit conference and so they did put these nice legends on here. And so you can read that legend as well as I can. But, so this is a rhabdomyo sarcoma. So whenever you've got a child with explosive proptosis and rapid tumor growth, you want to worry about rhabdomyo sarcoma. And so there's a couple of types of rhabdomyo sarcomas that we see and we don't good, we don't say it on here. What are some of the different varieties of rhabdomyo sarcoma? Okay, so embryonal or embryonal, I don't know how the proper pronunciation is, but that's the most common type. And what you see is when you look in these, you'll see these kind of tadpole shaped cells. So you'll see these cells that'll have this cytoplasm with a lot of pink, eosinophilic, staining material that kind of look like those round tadpoles that you see before they come into, turn into frogs. But if you look at them, you can see that it's pretty aggressive looking. And so if these aren't treated, they can grow pretty rapidly. And one of the other characteristics that you can see in these embryo, what do you see in rhab? Here. Yeah, so this is a muscle derived tumor and so you can actually see cross striations on these if they're differentiated. And the embryo tend to be moderately differentiated. So you can sometimes see cross striations and if you do a special stain, a trichrome stain, it really does show them. And so you can see over there to the right in the middle there, you can see the cross striations real nicely. So you can see cross striations, muscle differentiation for the embryo variety. Here you can see again, a nice one. Now if they're poorly differentiated, it's often hard to tell what these cells are. And so you can do immunoperoxidase stains, which will show that it is muscle in origin. So there are muscle specific stains that you can do. So these are the stains. One of them is by Menten, Desmond, and you can see that the cells stain positively for these. So we know that they're muscle derived. All right, so what kind is this? You already alluded to it? Yeah, so you can see why they call it alveolar. It looks like lung tissue. So it looks like you're looking at alveoli with a bunch of cells in it. So this could be a patient with pneumonia. These are inflammatory cells in the lung, but it's not. This is the kid's orbit. So you can see it, alveolar means it looks like alveoli in the lung. So you get these little septi in these round spaces with tumor cells. Is this important prognostically? Yeah, it's really bad prognosis. Yeah, so this is the bad prognosis. And so not that there's any really good prognosis in Arabian myosarcoma, but this is a particularly bad prognosis when you see the alveolar variety. You can't really make out the striations. No, once it gets to the alveoli, you don't really see the prostrations. It's really pretty poorly differentiated. And then again, if it's really poorly differentiated and you can't tell what its origin is, you have to do some immunoperoxidase stains. You know, does mental stain, muscle specific actin. So you can do some various immunoperoxidase stains that let you know this is muscle derived. All right, welcome back. So you're seeing this child. What are we seeing here? What would you be concerned about here? It's a graftose. What are these little things you see right here? Have somebody just put a foreseeing in or something? Actually, that's just their little crusty. That's the little crusty yellow stuff that's on the lashes. So is it probably more infectious like a preceptual or something? Okay, so in this particular one, again, you always keep rabdo on the back of the mind. That's good. And so again, when you're at boards, you know, it's almost like saying herpes when they show you a corneal lesion. If they show you a kid with an orbital lesion, you want to say, well, of course, rabdo is on the differential diagnosis and we need to rule that out, but it's more likely this. Always include that in a kid. But so this looks more like something that's pretty acute and possibly infectious. And so what kind of infections can look like this? A preceptual cellulose. Okay. Now, is it important to differentiate preceptual cellulitis from a regular cellulitis? Like an orbital cellulitis? Exactly. And so that's a key thing. So you probably want to do a scan because you're going to treat a true orbital cellulitis a lot more aggressively than you would a preceptual cellulitis and you don't want to miss that, you know, miss an orbital cellulitis. And so sure enough, this is the biopsy that was done and you can see this inflammatory reaction here where you've got a mixture of acute and chronic inflammatory cells that are pretty much diffused through the tissue. And here you see a close-up of these. Now, in addition to an acute cellulitis, what other lesions can you get that can look a lot like this, but not be infectious? Okay. What do we call the entity? We mentioned that just briefly before. The idiopathic orbital. Exactly. So we used to call it pseudotumor of the orbit, but people don't like the term pseudotumor. And I call it idiopathic inflammation of the orbit. And so it's the same thing. It's a lymphoid type proliferation. And so we want to talk a little bit right now about how you separate lymphoma from a benign, you know, idiopathic orbital inflammation. And again, this tends to be more on the side of the orbital inflammation. Now, when you are looking at idiopathic orbital inflammation here and you're looking at lymphoma over here, there's a few things you can do to differentiate it. First of all, on the benign proliferation side, the idiopathic orbital inflammation, you see lymphocytes, but you also see plasma cells. And you can see vessels growing through there. And you can see follicles in there. And so those tend to be on the benign side. Now on the malignant side, you have just a sheet of lymphocytes, no plasma cells. You usually don't have follicles. You usually don't have a lot of blood vessels through there. What's the one test we can do if we had to do one test to tell, you know, lymphoma from an idiopathic orbital inflammation? Clonality, exactly. So if you look at the lymphoma, they are monoclonal where the others are polyclonal. Now we can do that now on formalin fixed tissue. And so you can do immunoproxidase stains. You can say, okay, is it T cell or B cell? Is it, you know, Kappa, Lambda, et cetera? Now if we were gonna look at orbital lymphomas, what's the most common type of orbital lymphoma? B cell. B cell, okay. And know your characterization. Know the classifications of them. Because, you know, they've changed in my career three times now, the classifications. And I get sick of memorizing them. So I have to look them up every time. But the most common now is what they call a mantle zone B cell, small cell lymphoma. So that's the most common one of the, but this particular one tends to be inflammatory. And if you don't treat an inflammatory orbital lesion like this properly, this can happen. Eileen, what's happened here? No, no, that could be the same thing. It can, scures just mean scarred, scarred in. Exactly. So you used to get, they used to call these, you know, fibrotic or sclerotic pseudo tumors. And so once you get that inflammation, eventually calmed down, it can lead to scarring, fibrosis. You can even get a frozen orbit. In the days before they had steroids, these patients would go on and their orbit would just get sucked in completely with this fibrous, skierous scarring material. So you want to treat the pseudo tumor lesion before it gets to this point. And then of course, here's our young man with, you know, similar things. You look at it, you can't really tell what's going on. And here again, if you look at the scan, you see this diffuse infiltrative lesion of the orbit and we see this. Now how is this different from the previous ones we've seen? Yeah, so you see a sheet of these medium sized lymphocytes when you're looking at them here. And then we do immunoperoxidase stain. And again, these were all B cell lymphocytes. And then when you substained them, you could tell which they're from. Now you can also, if you get fresh tissue, do flow cytometry, which you need fresh tissue for that. If the tissue is fixed in formalin, though, you can still do staining for clonality, but it's immunoperoxidase stains. And so some of the people over at the main hospital like the flow cytometry better, others say none of the immunoperoxidase is fine. So if you can get your hands on fresh tissue, they can do the flow cytometry and they'll give you exactly what percentages of what type of cell. So you can see, okay, it's 80% B cells and such percent T cells and so much of this and so much of that. So the clonality that's done with flow cytometry gives you a little bit more precise information, but even on formalin fixed tissue, you can tell lymphoma versus the idiopathic orbital inflammation. Now there's a continuum in between. It's not just there's one here and one here. The hard part is in between, there is a lesion that's characterized by proliferation of mostly lymphocytes, but it's not monoflonal. And so this is called an atypical lymphoid infiltrate and those are really tricky because they almost look like lymphomas. And so we spent a lot of time trying to subdivide these. Again, I'm not sure if it makes that much difference. 10 years later, a lot of these do go on, even if they're not quite lymphomas at the time go on and become lymphomas. And the longer you follow these, the more chance you have for systemic involvement of lymphoma. And Fred Jacobiak when he was in New York had a bunch of people who had just orbital lymphoma and when he followed them at five, 10 and 15 years out, by 15 years almost 75% of them had developed systemic lymphoma. So it's interesting at 10 years it was about 50%, at five years about 25%. And so the longer you follow them, the more chance they had to develop systemic lymphoma. So you really gotta keep a close eye on these patients. All right, I'm just gonna show you a couple of ugly orbital lesions here, tumors that can't involve the orbit. Now remember the orbit is a big sink, it's a big repository with a bunch of fat and some other things in it. So you can get primary tumors of the orbit which we talked about, but you can also get tumors from elsewhere invading the orbit. So Brian, where can you get other tumors that can affect the orbit? They said you can get them from the eyelids or the conch or from the sinuses. Exactly, so you can actually get tumors invading from the lid. So any of the lid tumors can be back into the orbit. Any of the tumors growing from the sinuses can go into the orbit. And then lastly, you can actually get metastases to the orbit too. And so this is an exenteration where you remove the entire orbital contents because of the tumor. And the reason I'm trying to show it to you is look at the color up above there and that's real color here. What kind of color are you seeing here? Kind of a dark, almost a black or a bluish black. What would you be concerned about if it's a really dark lesion? So yeah, just talking about the lead lesions, the lesions from the front, they were worried about the melanoma. Yeah, so this particular patient had actually a conch melanoma that invaded into the orbit and required an exenteration. You can also get other tumors that grow from the lids. And those now basal cells usually don't invade unless you let them go for a long, long, long time. But squamous cells can invade into the orbit and so you can get lid tumors that can invade into the orbit. And you can get, this is a squamous cell that invaded into the orbit from the lids. This was a melanoma. So you see these bizarre, big melanoma cells. So you can get secondary invasion into the orbit from the lids. Now, you can also get distant metastases and so it's indicative of the most common tumors. And so in women, if you're thinking of metastatic tumors, you think of breasts. Men, you think of lung, exactly. And so although that may be changing and keep an eye on that because when cigarette commercials used to be allowed on TV, they had one that was for this company. They decided they were gonna aim it toward women. So you see this really sophisticated, sleek-looking woman with a cigarette. And this was her brand and she was making it in business. And so their slogan was, you've come a long way, baby. Seriously, that was the slogan in the 60s. And so that's true now. And so women have come a long way. They smoke just like men now so they can get metastatic tumors from their lungs just like men do. And so even though breast was the most common, lung is slowly creeping up as women are smoking more. And so you're seeing the lung almost even with breasts when you look at metastatic. All right, back to Reese since we got to make up for when you were gone. So this is what Reese looks like when I just ask him this question again. This is you on oral boards. So what are we seeing here? The injection where it's low-key. It's almost kind of here where the rectus muscle's insert. So what would this be? I'd be worried about thyroid, IVs. So what's the most common cause of bilateral proptosis in an adult? Thyroid disease. What's the most common cause of unilateral proptosis in an adult? Thyroid disease. Good, so you guys have listened at one time. So pound that in there. All right, thyroid disease. And so this is classic Graves picture. Now, in this particular scan, is this a worrisome scan if this were that patient? Exactly. So when you get, you know, the muscles will swell in thyroid disease. When you get this swelling posteriorly where it's very crowded at the orbital apex, you can actually get an optic neuropathy from compression. So those are the ones you really worry about. If the muscles are more anteriorly and the patient has a lot of proptosis, you worry actually a little bit less about those because it's automatically decompressing outward rather than, you know, compressing on the optic nerve inward. And so this is a autopsy eye that I got ahold of a picture of. And look at the swelling of the muscle. Now, how do we tell the difference when you look at a muscle that's involved with the inflammation from thyroid as opposed to an inflammatory myositis? Exactly. If you look at this picture, here's the tendon, tendon is spared. Here's the muscle itself diffusely involved. And so if you have a myositis, it can go all the way to where it inserts into the glow. But if you've got thyroid, it tends to spare the tendon. So you can see it sparing that. Acutely, you tend to get swelling of the nerves. And so you get lymphocytes in there. You get this myxoid pattern. They get really acutely swollen. And then just like pseudotumor of the orbit, kind of in thyroid, if you don't control it well, you can eventually get scarring. So you can get scarring of those muscles. They can contract and you can get significant problems with trabismus. All right, last little lesion here. Let's see. I guess we did, Eileen. You got a short one, but we'll go back to you because that last one was short. This is from a young child. This was fortunately taken out of their orbit hole. And I'm trying to show in this picture that we're trying to shine a light through there. And when you shine a light on there, it almost lights up like it transilluminates. A cyst, okay? And a big cyst. And we look at that cyst and what do we see here? And when you cut it, this yellowish material is really disgusting and smelling too. So what do you think this could be? Okay, so this could be a dermoid cyst of the orbit and it's filled with, what is this yellow material? It's keratin. Keratin. So when we look at the lining of a dermoid cyst, what is the epithelial lining? Okay, and what else is here? Yeah, so there's some hair follicles, there's some sebaceous glands, and so the key is the dermoid cysts of the orbit tend to have not only epithelium, but epithelial appendages. Hair, sebaceous glands, things like that, even sweat glands sometimes. And so dermoid cysts in kids, usually we think it's some kind of a congenital remnant where superficial epithelium gets pinched off at the area of one of the sutures, suture lines of the bones, and then grows in the orbit. Now, these again will push out and form a pseudo capsule. So if you get these out whole, it's curative. If it breaks when you go to take it out, keratin is really inflammatory, and so you can get some raging inflammation if these things break up when you try to take them out. So you gotta be really careful that you take these out whole. Then we say goodbye, looking out toward the port in the old city of Edinburgh. So I think next week you get a time off from me, but then it's like March 1st is tumors. And so not only are we gonna do tumors in adults, we're gonna do tumors of children and we're gonna do the differential diagnosis of leukocoria. So know that, okay? All right.