 All right, you guys ready? You had a week off? Hopefully that gave you double time to read about optic nerve. I know you sit further back. You think I can't see you back there, but I can. So all right, so we're going back to Portugal here. So this is the Moorish Castle, Castelo das Moros. And this is about a 10th or 11th century Moorish Castle. And that's where it sits. And what's cool is it sits, obviously, if you build the castle, you're going to build it up on a hill where it commands the entire valley and make big stone walls out of it. So you can see it's stacked up on the hill. And what's cool about it is this is not the US. Now, if this were the US with lawyers and liability, there would be huge fences all around that. You wouldn't be able to go on this. But if you look at this, you can climb all over this thing. And I mean, like right there, if you slip and fall there, you can die from that. But it doesn't matter, because there's no lawyers in this part of Portugal. So you can literally climb to the top and take your picture with the flag and wander all over this old medieval fortress. It's got a great view of the valley. And so you can just kind of enjoy the view. And as I said, it's about 1,000 years old. And so it's, well, 800 years old. And so it's quite amazing that it's still standing. And you can see here, as you walk on, that's me on the little flag there. And then you can go up on the flag here. And you can see it overlooks the valley, and then eventually goes out to the ocean. And you just walk along here. And you can just walk along. They did put a guardrail up there. And that's like their only concession to safety. Otherwise, there's no guardrails on this whole thing. You just kind of climb through the whole thing, which is fun to do. And this is looking down into the valley. This is one of the old palaces that they've turned into a resort now. But you can see, look, there's the rocks. I mean, you slip there. You could die. It's kind of interesting to climb all over this place. And there you see the valley spreading out beyond it. And lastly, here's the other climb. You go up to the highest part here. So you've got lookouts all over here and here. So it's always kind of fun to do. OK, we're going to talk about the optic nerve today. And this is just a picture of a normal looking optic nerve. Now, let's start with Becca. This is an optic nerve in a sagittal section. What stain is this? It's actually, it's a trichrome. And so a trichrome stain, what a trichrome stain is, is it will stain connective tissue blue. And so that's how you know it's a trichrome stain. It'll stain mesenchymal tissue, nerve tissue, and all pink or red. And so if you look right here, here are the fibers, the columns of axons going down here, and they are red. And then you see the connective tissue in between in blue. If you look at it in cross-section, you've got the same thing there. Now, the analogy I like to use to remember what normal optic nerve is, is I like to use the analogy of a fiber optic cable. So each axon, as it comes through the lamina crebrosa, becomes myelinated. That's why the optic nerve, when you look at the nerve head, is only 500 microns. When you go behind, it's 1500. Because each of the axons gets myelinated. So that's a single fiber optic cable, fiber optic little strand, if you will. And it's got myelin around it. So it's got a little bit of plastic around it. Then they are bundled into bundles. And in between these bundles, there are little pioceptae between the bundles. So those are the bundles of the fiber optic cable. And lastly, when you bury that fiber optic cable into the ground, it is surrounded by a thick steel tube, i.e. the optic nerve sheath. And so think of it that way. And you can get an idea of what's going on there in the optic nerve. So this is in cross-section. Tina, what are these? All right, so note how closely related they are when they're coming in. Remember when we talked about retina. Most common cause for a central retinal vein occlusion is actually arteriosclerosis. So it's a sclerotic artery pushing on the vein next to it. All right, what are we looking at right here, Tara? So here's the bundles of the optic nerve here. What are these right here? And what is this area? This is the sheath here. Actually, the outside is over here. So this is the sheath. What is this area here called? Remember, optic nerve is an extension of the brain. Exactly. So you've got, just like the brain, you've got a dura, i.e. the optic nerve sheath. And then you've got an arachnoid, subarachnoid space. This is where CSF fluid goes. And these are the arachnoid granulations that live in this area. And then lastly, these are these little PL septae that come from there. So you still have, just like the brain, you've got the sheath, the arachnoid subarachnoid and the pia, which then form this into columns. And here you can see it in a longitudinal view. So in between here are these PL septae. You've got some oligodendrocytes that create the myelin around here. What are some of these other cell bodies that are in between here? Where are the cell bodies of the nerves themselves? Exactly. So these are just axons. So what other cell bodies are in here? Exactly. So you've got the oligodendrocytes that make the myelin. But you've also got astrocytes in here too. So any kind of tumor that can affect astrocytes can show up in the optic nerve itself. So you've got astrocytes in there too, and maybe some little microglial cells, a few of those that are in there. And again, we talked about this. This just shows you the central retinal artery and vein. And the closer you come to the optic nerve head, the closer those vessels are. So finally, when you're coming through the optic nerve head, they're right next to each other. All right, what do we see in here, Niko? So what would we call this? Exactly. So it's not uncommon that you see a sclera rim here and a little bit of some sclera show here. And in myope, you see that all the time. But myope, the nerves are large. Whereas if you look here, this is the nerve right here. That's really small. And so this is optic nerve hypoplasia. Is that usually unilateral or bilateral? Bilateral. And the other thing is it can even be inherited. So sometimes when I'll see a kid with optic nerve hypoplasia, you just ask the parent if you can look. And they'll have it too. Does this cause any significant issues with vision? Not only that, but in fact, the vast majority of optic nerve hypoplasia have normal vision. And so really, this is not a significant pathologic issue. So most people would just run of the mill, optic nerve hypoplasia actually have normal vision. What do we see in here, Chris? Yeah, so you see this kind of inferior just area where the optic nerve doesn't form. You're kind of looking at an area of just sclera out there. So this is an optic nerve coloboma. What does coloboma mean? Yeah, it does. It comes from the Greek. And so what causes it is it's an incomplete closure of the ophthalmic fissure. So remember in early, early embryology, when you get that infolding of the neuroectoderm, eventually it will come together. And that little area, inferior, a little bit inferior nasal, is where it fuses. And if you get improper fusion, you are left with an optic nerve coloboma. So it's an improper closure there of that. Lee, what are we looking at right here? So what do they call this when there's a massive staphyloma around the optic nerve? Kind of the ultimate coloboma. This is called morning glory syndrome. And so morning glory syndrome. What is a morning glory? There it is. It's a flower that's shaped like a trumpet horn. So if you were to look at this in 3D, that is actually moving away from you. So it's almost as if not only did it not form, but there's a huge outpouching, like you're looking down the barrel of a trumpet. So when you look right here, you see these little vessels are in focus here and they're all blurry here. And that's because that's moving away from you. So it's almost like a big trumpet horn that you're looking down in. And so that's kind of the ultimate optic nerve coloboma. It's called a morning glory syndrome. So morning glory. Nathan, what are we seeing right here? All right, so this is an optic nerve pit. Now, they're not always this blatant. I mean, you look at this, oh, that's an optic nerve pit, but you look at these, sometimes it can be really subtle. And so it's not uncommon when you look at these optic nerve pits, they're not as blatant as that right there where you can see that optic nerve pit. And when we look at the pathology, what will happen is you'll get almost an area here where you get a little pit where that optic nerve doesn't quite match up with where the sclera is here and you get a gap in there, if you will. You can even get cerebral spinal fluid coursing through here and underneath the macula. So these people with an optic nerve pit, it's not so much that the pit causes visual loss, but that you can get actually fluid underneath the macula that can cause visual loss. This is very tough to treat because if you're gonna do laser and wall that off, what you'll do is you'll kill off the fibers coming in the optic nerve bundle temporarily. And so these are actually quite difficult to treat when you get a pit with leakage like this. What do we see in here, Josh? Exactly, so this is myelinated nerve fiber layer. So remember the oligodendrocytes don't usually put the myelin on the axons as they're coming out until posterior to the laminar fibrosis. But sometimes that myelin will pop forward. And so you'll get this myelinated nerve fiber layer. And that's, it's important that you recognize that because if someone's just looking in an eye, saying undylated people in the ear, they're gonna look in and they're gonna say, oh my God, papillodema. And you know, it's personal get, holds drilled in their head. And so I always warn people with this. I said, listen, you've got some extra insulation. It's called myelin on your optic nerve. And I tell them, I'm telling you this because if anybody ever looks in your eye in the ER and starts getting really excited, tell them, you know, no, no, no, no, no. This has been there since before I was born. And so this is just myelin spilling over. What do you think the patient's vision is? Yeah, you'd think so, but it's not. It's actually normal. The only difference is, is this myelin tends to block off a little bit of the light actually coming through peripepular so they'll have a large blind spot. But the myelinated axons still work. And so there's still signals getting through there. So patients with this will have a large blind spot, but they can have normal vision. And in fact, most people with myelinated nerve fiber layer don't even know it. So you just be sure to tell them. Because again, you don't want them getting their skull drilled for high pressure. All right, Becca, what are we seeing here? Exactly, so this is, again, you don't want to call this papillodema because you want to look carefully. And if you look, you don't see engorge of blood vessels. You don't see hemorrhages there. But you see that nerve is actually elevated. And there's this little bumpy quality to it. And so these are optic nerve juzen. Now, the tricky part is when juzen are buried, sometimes you look at a nerve and you'll say, man, that looks elevated, but it's really, it's not engorged. There's no hemorrhages. It's not that swollen. And so you can actually get buried juzen that can sometimes fool you. So you want to be really careful. Now, these are some just showing you some blatant optic nerve juzen. And you see it's irregular and you've got these. And now these, the one thing that's helpful is they calcify these optic nerve juzen. Why is that helpful? You can ultrasound. Exactly, you can do a B scan ultrasound on here and these will light up. The other thing they'll light up on is a CT scan. To do a CT scan, they'll light up. But if you can just put a B scan ultrasound on there, you find the optic nerve where it's leaving. And these will light up. And as you turn your gain down, the eye will start to disappear. But calcium really reflects that ultrasound. So you'll get these juzen will just stay here. So I always, if they're buried juzen, I'll always send them to Dr. Harry and get the ultrasound. Now, this is a cadaver eye, but this is one where I don't think anybody would miss this. And sometimes they're more subtle. I mean, look at this. You say, wow, could that be papillodema? I don't know. So you really want to put a B scan on there. And then you'll be able to tell for sure. And here we have a CT scan. And there it is right there. So they tend to light up on CT scan, which is helpful. And there you've got another one. Look at those little juzen on there. So they do light up. So I wouldn't jump in and do a CT scan. I mean, ultrasound's really easy to do. And you don't have to do a CT scan. Now, here's a path view. This is the optic nerve cut in cross-section. And here's the nerves going to go out behind here. And here's the retin over here. And sure enough, there's this juzen. And the juzen tend to be calcified and hyalinized. And so they're in front of the laminar crebrosa. But the deeper ones are buried down here instead of up here. And they're hard to see. And so there you can see the calcified juzen. Now, Dr. Katz is doing some studies to see what they do. And over time, as these get bigger and bigger and come forward, they can't impinge on the nerve fiber layer coming in. So patients can have focal nerve fiber defects where these juzen are. They don't lose vision completely, but you can get these focal defects. And so they're not completely innocuous. Problem is, we can't treat them. Can't go in there and take them out. So that's a real problem. All right, and here we can see again, that's calcium. See that right there? Calcium, calcium, those are juzen buried in there. All right, Tina, what are we seeing here? All right, so other things you can see. Look at the little hemorrhages there. Look at the engorgement of the vessels. Optic nerve, right? So optic nerve edema, and it's critical, especially when you're taking oral boards. The term papillodema, what does papillodema mean? Exactly. So you want to be really careful. So don't throw out the term papillodema. They'll try to flu you on oral boards and you'll say, okay, this is optic nerve swelling. And they say, well, what's the differential? Well, if it were secondary to, you know, increase intracranial pressure, we would call it papillodema, but it could be other things. And so don't jump in and say papillodema right away because they'll say, okay, tell me about that. And then, you know, they'll lead you down that wrong path. Okay, and this is one I'm hoping that even a medical student could get. There's no students, even a fellow could get this. So you can see the marked swelling. Look at the hemorrhages here. Look at the engorgement of the vessels. So this is like grade four, grade five, depending on the classification you use. This is the ultimate grade of papillodema. So that's as severe as it can get. Now, if you're looking at the optic nerve here, you can see now, look out. Remember, the nerve comes across like this. Look how far out that goes. So not only is it markedly swollen, but you have blood vessels that are engorged here and you actually even have hemorrhages on the surface. So what's a patient's vision usually like in papillodema? How about most of the time? Exactly. So it's an enlarged blind spot, but the vision can be normal and that's important. So this is one where the nerve looks terrible, but the vision is good, as opposed to ischemic optic neuropathy where the nerve looks pretty good and the vision is terrible. And so kind of the opposite. This looks bad, but the vision can still be preserved aside from, again, an enlarged blind spot. And here you can see that's actually forward bowing of the lamina crebrosa from that increased pressure behind. It's actually pushing the lamina crebrosa forward. So you get papillodema from that. Tara, what are we seeing here? Yeah, this is more kind of focal almost. You've got some swelling up here, down here, doesn't look too bad. All right, and so this is a lot more subtle, kind of a subtle swelling. These are the more difficult ones to tell what's going on. What's in your differential here? Okay. All right, so those are kind of the two major groups you want to think of. On one side, it could be ischemia. So it could be the arteritic or non-arteritic optic nerve ischemia. On the other hand, it could be a inflammatory demyelinating disease too. And so you want to look at optic neuritis also. So in an acute case where you've got some AION or even optic neuritis, you can sometimes get a little bit of swelling there acutely. It's very subtle, but these people tend to have quite significant visual loss. And the nerve that looks just subtle like that. All right, why am I showing you this? What is this structure? Exactly, now is that a normal one or an abnormal one? Yep, looks pretty normal. So let's say the previous patient we showed you is 80 and they have sudden visual loss. And then they say, you question them further. Well, you got any other problems? Yeah, I just feel crummy. I'm losing weight. I'm sore. You know, people don't come out and say I have claudication. You have to ask them. You have trouble chewing. Yeah, yeah, I thought it was TMJ, you know, something going on like that. And so one of the things with AION and an older patient is you want to make sure that you're not going to miss arteritic AION. All right, Shrave, what are we seeing here? Okay, what's thickened? So here's the lumen. It's markedly narrowed. What part of it is from here to here? That's actually the intima, exactly. So the intima's thickened. And so remember, you do not get temporal arthritis in normal arteries. You get it in people with significant arteriosclerosis. So something, no sclerotic arteries, changes things. So you see the intima's markedly thickened. You said the internal elastic lumen is pretty chewed up. Now, this layer here would be the median. Are you seeing any normal muscle fibers in there or anything? Yeah, so I'm not seeing any normal muscle fibers. Let's look closer, and sure enough, we see that. What's that? So thus the name, giant cell arteritis. So when you see the giant cells, they're usually either internal of the muscular media, the internal elastic lamina, or they're external to it or they've chewed the whole thing up. The other thing that you can see not uncommonly is you can see some little blue cells. Even out here, you'll see a little cuff of blue surrounding this, and so you'll see a little cuff of lymphocytes. Now, Niko, we're looking at a temporal artery right here. Now, I'm not seeing any giant cells or lymphocytes, but that sure looks abnormal. Tell me what's going on here. Yeah, internal elastic lamina's gone. What is this layer right here? Not quite. So that's the media, muscular media. Look over here. It's just gone. So what could this be? Exactly. So this is what we call a so-called healed arteritis. So you look and you see right here, here's the intima really thick, internal elastic lamina gone, muscular media here and about a third of this gone, it's like something chewed it up. And so this is what a healed or a treated arteritis looks like. So this is someone who's gotten cortical steroids, they've calmed it down, and then you see this picture. So this is after it's been treated or after the arteritis goes away. So this is what an artery looks like, post arteritis or healed arteritis. All right, Chris, what do we see in here? It's kind of pale here, but it's kind of fuzzy over here still. So again, one of these funny-looking nerves. All right, so instead of 80, this person is 20. Yeah, so this would be more in the optic neuritis mode rather than the ischemic or arteritic change. All right, so we're looking right here what do we see in here? Give you a hint. This was the optic nerve head right here. What's happened here? Yeah, these are the actual normal central retina artery and vein going in. And so if you look right here, here's some axons and nerve fibers here, here's some here. Look at this, this is just wiped out. So this could be two things. This could actually be an AION, non-artoretic, which looks like this, or it could be after an optic neuritis, so hard to tell. And so when you see a focal area here more in the center, this is actually more, it's just an AION, a non-artoretic AION. When you get the changes from optic neuropathy, I'll show them, or optic neuritis, I'll show you that in a second. So this is again, an ischemic focal area more in the center. This is probably more an AION. Boy, these get tougher. They all look the same to me when I look at these, Lee. What if I say this is unilateral? What's your differential? And you can do inflammatory also, or you can do neuritis also. So again, tough, tough differential. Infiltrative lesions can give you unilateral disc swelling. This could be an acute AION, right when you first see it, this could be an acute neuritis. So tough to tell when you look at these. And then we look at the nerve right here. This is a cross-section of nerve. What do we see in here? Believe it or not, this is normal nerve right here. All of this is normal. The abnormality is right here. Yeah, you've got a focal area of atrophy here, and some areas where you're not seeing the normal myelin around there. So what could cause this? Actually, you don't really get infectious processes in this area, but inflammatory and post-inflammatory, this turns out to be an optic neuritis. And when you do optic neuritis, when you see this segmental defect here, that's a real tip-off of an optic neuritis, a segmental defect with demyelinization. And this is usually due to optic neuritis. And what's the main disease we worry about with an optic neuritis, associated disease? Yes, MS. And so, be familiar when you guys do neuroop of all the studies that have been done looking at when you get an optic neuritis, how you treat it, and what the association is. And so, at one time, we would treat optic neuritis with oral steroids, and it turns out that's really not a good idea. So you blast them really hard with IV steroids, and then taper them off, and that'll actually bring the vision back quicker, and help the neuritis go away quicker. In the long run, say six months out, after you've treated an optic neuritis compared to an untreated, what's the level of vision? How about treated versus untreated six months out? Yeah, so at six months, there's no difference, and that's the important thing. When you use the IV steroids and treat them, the vision recovers quicker, but at six months, it's still the same whether you've treated them or not. But what we have found now when they're doing these optic nerve treatment trials is that if you blast them with steroids early, they have less chance of developing MS, at least for the first couple of years. And so there's some advantage to treating them, not only bringing their vision back quicker, but in the prevention of MS from developing, which is interesting. So this is an optic neuritis, and what you see in these, this is longitudinal, this is normal down here, and right here, you've got this focal or segmental loss. And so this is classically what you see in an optic neuritis or an MS. Now, Nathan, what do we see in here? So if you look right here, this is the sheath. Here's the optic nerve. Look how wide that subarachnoid space is. And so this is a sign of optic nerve atrophy. Now, say you had an AION and you wiped out your nerve, how long does it take for that nerve to turn pale or you can see it when you look into the fundus? Yeah, it takes a long time. And so don't let the lack of pal or fool you. And so it can take weeks to months for that nerve to turn pale, for those cells to really die off enough that that nerve gets pale. This is end stage. Now, you don't know what caused this. This could have been ischemia, could have been inflammation. This is just an atrophic optic nerve, real widening of the subarachnoid space. So just end stage optic nerve atrophy. All right, what do we see in here, Josh? Yeah, you see how it's fuller up here? So you get the idea that maybe that eye is coming out a little bit. It's a little bit fuller. What else do you see with that eye? So pupil's a little bit bigger there. What else? Yeah, look at the red reflex here. It's dead center in the pupil. Where is it here? Bit high, which means that that eye is actually lower. So you've got an eye that's sticking out and that's lower. How long is the, sorry, how long? How old is this patient? Yeah, so it's an adolescent. And so now you start thinking, gee, why would an eye on one side be sticking out and down a little bit in a 12 year old? So we say, okay, we're gonna go ahead and we're gonna look inside the eye and what do we see in here? And that's just kind of the picture that's taken. But there's a subtle finding on here. Look at these horizontal striations. It almost looks like, remember the Japanese rising sun, you know, with the sunburst coming off it? It almost looks like that. So you see these, what the heck are, cause of these kind of striation looking things on here? Exactly, so those are called choroidal folds, actually. And so what can cause it a mass within the muscle cone? So mass within the muscle cone pushing forward can cause this. Now, don't go away thinking that that's a sign of a tumor. The most common cause for choroidal folds is hyperopia with a short eye that's got a flattened posterior surface. And so if you just see choroidal folds, it could just be a hyperopic short eye. But it also can mean a lesion within the muscle cone. All right, Becca. So we're looking at a 12-year-old with a proptotic eye and choroidal folds. What would be something you'd worry about? Do radios usually occur within the muscle cone? No, so you'd worry about an optic glioma. And the problem with them is if you have a lesion within the optic nerve, around the optic nerve, eventually it can choke off all the fibers and give you this. This is a completely atrophic nerve. But let's say that this is this child's scan. What do we see in here? Yeah, if you look, it doesn't look like there's a nerve in the middle and then something's surrounding it. It's like the entire nerve is big. We call this a fusiform. It almost looks like a big sausage of enlargement there. And sure enough, we remove it and we get this. Tina, what would you be concerned about here? We just removed that lesion that we saw on there. What do you think this is? We just said it's a 12-year-old with a fusiform enlargement and you just removed it. What's the most likely etiology? Exactly, this is an optic nerve glioma. So when you see, I don't ask hard questions. So this is a glioma. And if you look at it, look, here's the optic nerve down here. Here's the sheath up here and you see part of the sheath is pulled back and you see this tumor is actually within the optic nerve. And so when we look at it, here's one where actually the whole globe came out. You can see there's this large fusiform enlargement within the nerve itself. So what's the source of the glioma? What are the cells that it comes from? Astrocytes, okay. So how do we grade astrocytomas, just from the brain or from anywhere? One to four, so what are these usually? These would be a one. A one, exactly. So this is what some people would call these, you may hear the term juvenile pylocytic astrocytomas. Pylocytic means hair-like. And I'll show you the path and see why they call it hair-like. And so these are low-grade astrocytomas. These are grade one, as opposed to glial blastoma of the brain, which is a grade four that people die of. And so these are usually a grade one astrocytoma. They'll call them a juvenile pylocytic astrocytoma or optic nerve glioma. And then we look at them and again, I think pathologists spend a lot of time in the dark in the basement sniffing formalin and so they sometimes see things I don't see and so this is called hair-like. I don't know, okay, sure. And so it's a low-grade and by low-grade, I mean when you look at the nuclei, they don't have mitotic figures, they don't have nucleolide, they're just kind of just a low-grade, slow-growing proliferation. And here you can see one other feature, Terra, what's the most, what's a common pathologic feature that's shown here that you see in these lesions? Rosenthal fibers and look at these little pink eosinophilic staining inclusions here in the cytoplasm. These are called Rosenthal fibers and so they're kind of a degenerative gathering of material in the cytoplasm of these low-grade tumors. And so people argue exactly what causes them but it's almost like there's just a buildup of some waste material that builds up in there and so these are called Rosenthal fibers and so these are a real tip-off in low-grade optic nerve gliomas. Some people may even argue that these might even be congenital because when you look at kids with these, especially if they extend back into the canal, you'll see bony remodeling, which means that these are there for a long, long time and so certainly these are very slow-growing, not malignant but if you're growing inside of a nerve, you're slowly killing off that nerve and the problem is to treat these. Well, if you remove them, okay, you lose the side in the eye completely, you can irradiate them and it may shrink them a little and slow the growth but again, it doesn't bring the vision back and so these are difficult tumors to treat and here you can see this is an optic nerve down here, a little bit of remnant normal nerve and you can see right here, this kind of hair-like astrocytoma growing here within the optic nerve sheath. Now, Shrav, what are we showing here? Yeah, so these almost look like the somoma bodies that you see kind of in the subarachnoid space in the meninges. The reason I'm showing you this is if you showed me this picture, I would say, whoa, meningioma but you can get reactive changes in the optic nerve outside of a glioma and so this turns out to be a kid with a glioma so the reason I bring this up is, sometimes people say, well, we're not sure what this is, we're gonna do a biopsy of the nerve but we're not gonna take it all the way through because we don't wanna kill off the nerve and so what happens is, is they do a little superficial biopsy and if you get just the arachnoid and the tissue right underneath it, you can get these reactive changes that look just like a meningioma in these kids. You wanna be really careful if you're gonna do a biopsy that you just don't get a little surface biopsy and here again, you can see that kind of a reactive proliferation of the meninges on the surface of a glioma. All right, Nico, what are we seeing here? Yeah, so when you see that kind of straight out proptosis, you wanna worry about something intraconal again, something in there pushing that eye out as opposed to extraconal in the orbit so you'd be concerned here. Now, obviously looking at the age, the person gray hair, probably in their 70s and you are allowed to make jokes of your own kind so she's obviously a Greek grandma because you see the mustache and the whiskers and so I thought all grandma's had mustaches because they kind of tickle you when they'd kiss you when you were a kid so this is a nice grandma with a mustache and so this is a different differential than the child we showed and so what would your main concern be here in somebody who's this age? You could be concerned about a more like a meningioma rather than a glioma. Now, the one thing to remember is if you see a tumor that's outside the normal age group, it can be more aggressive so although they're rare, if you have an optic nerve glioma in an adult rather than a kid, that could be aggressive. If you have a meningioma, not in an adult but in a kid, that can be more aggressive and so they're rare but if you get a tumor that's outside that normal age group it can behave more aggressively. What do we see in right here? Yeah, one more, you know. Pimp Chris here. All right, so we've got a little optociliary shunt vessel. What does that tell you? Exactly, so it's kind of being squeezed down and the blood supply's being disrupted and so it's trying to get extra blood by forming these little dilated optociliary shunt vessels and so these are important, these shunt vessels, they're a sign of chronic ischemia of the nerve. So what do we see here, Chris? Exactly, so you know, if you remember if you look how the tram goes up, you know you'll have the center cable and then there'll be these other two cables next to it so they call this the tram track sign and you see there's the nerve inside still intact and then there's this around the nerve. So as opposed to the glioma growing from the nerve itself this is growing around the nerve, under the sheath but around the nerve. So this is a classic sign of a meningioma. It's a classic sign of meningioma. This is an extreme example. This was an exenteration. Here you see the globe, here's the optic nerve, here's this massive tumor growing around the nerve and filling half of the orbit. So if you look at these cells, these cells are these meningothelial cells growing and so you see they've got some nucleolice, some chromatism, some activity. They almost look like squamous cells to me. They've got this kind of a pink cytoplasm here with the nuclei there and so this is a meningioma. Sometimes they don't have quite that nesting pattern. They can be a little bit more diffuse but again, the pink cytoplasmic background, they almost look like squamous cells when you look at them. So Lee, what is this right here? Sumoma body. Now, see you knew that because Shreve already said that, spell it. Good, so Sumoma, it's a double M in there and a PSO, so Sumoma body. And so these are hyalinized, sometimes calcific, little areas where you form these round inclusions. So here's the meningothelial cells and these are all through here. So they have hyalininum, they have calcium in them and so these are a real tip off that this is a meningioma and so this is optic nerve meningioma. Again, these are tough to treat because say you do surgery, you wanna peel off the meninges. You know, the meningioma, open up the sheath, peel that off and yet leave the nerve intact but a lot of the blood supply of the nerve comes from those little penetrating vessels in the periphery so when you peel off that meningioma you kill those off and so again, this is a slow growing tumor so it reacts a little bit to radiation therapy but these are tough to treat just like gliomas because the problem is that the treatment often kills the nerve. And so it's like the Vietnam analogy. Well, we bombed the village to save it. Well, okay, but it's still a dead village and so that's a problem and so you'll often end up disrupting the optic nerve itself when you go in and try to treat it so it's very, very difficult to treat. All right, Nathan, what are we looking at here? Yeah, so an intraconal mass, so on a sagittal scan here, so we've talked about gliomas, we've talked about meningiomas. What else can cause a growth inside the cone beside those? Testuses. Very rare in the cone. The orbital metastasis is very common but not usually in the cone. Schwannoma, exactly. So don't forget, you do have some Schwann cells in there too and so you can get a schwannoma intraconally. It may not be within the nerve but it can certainly be adjacent to the nerve and what's another word for schwannoma that you may see? Nerylimoma. And again, if you can spell that in somoma you'll be doing better than I am but that's another way of saying schwannoma. All right, so Josh, there's a couple different patterns of schwannomas. Do you remember the different patterns of schwannomas? All right, so which one is this? All right, so surprisingly enough this was something that was not described by a German or an Austrian. It doesn't even come from the Greek so Antoni was an Italian pathologist and so Antoni divided these into A and B so the fascicular spindle-shaped schwannomas are called Antoni A and obviously this would be Antoni B and it's more of a myxoid. It's got kind of this background of this whitish myxoid looking tissue and so Antoni A, Antoni B. I don't know if they'll ever ask you that on boards or OCAPs but they might so you need to know that. Not really, uh-uh. With Antoni B sometimes it's tricky to make a diagnosis because these myxoid areas can actually just have some large areas where they'll almost form kind of cystic gatherings of stuff and so it's kind of tough to make that out. All right, so we're looking at the, this is from the Moorish castle looking back at the palace that I showed you guys a couple weeks ago so this is where the Moorish castle is and that's the palace up there. Now all right, so next week is orbit. So read up on your orbit. All right, thanks.