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Hello and welcome to Noon Conference,

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hosted by M R I Online Noon Conference connects the global radiology

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community through free live educational webinars that are accessible for all

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and is an opportunity to learn alongside top radiologists from around the world.

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We encourage you to ask questions and share ideas to help the community learn

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and grow. Today we're honored to welcome Dr.

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Gloria Guzman Perez Creo, and Dr.

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Rami Alday for a live case review entitled Adult Super OID Neck.

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Dr. Guzman completed her radiology residency at West Virginia University and her

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neuroradiology Fellowship and Research Fellowship at the Mallinckrodt Institute

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of Radiology at Washington University in St. Louis,

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where she's currently associate professor of radiology.

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She has special research interest in advancing neuroimaging techniques,

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including advanced diffusion imaging for head and neck cancer diffusion spectrum

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based imaging and molecular imaging of brain tumors with FDO ppa in the

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evaluation of I D H wild-type glioblastoma in additions to outcomes and

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translational research of M R I I M R I in the field of neuroradiology imaging.

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Dr. Alday completed residency at U T M B and Fellowship in neuroradiology at

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Mallinckrodt Institute of Radiology.

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He specializes in neuroradiology cancer interpretation in the brain, spine,

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and head and neck region,

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and is currently an assistant professor at MD Anderson Cancer Center.

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At the end of the case review,

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please join them in a live q and a session where they will address questions you

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may have on today's topic.

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Please remember to use the q and a feature to submit your questions so we can

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get to as many as we can before our time is up. With that,

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we're ready to begin today's case review. Dr. Guzman, Dr. Alday,

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please take it from here.

1:51

Hi everyone. Uh, thank you so much for joining us today. Um,

1:55

and thank you Ashley, for such a nice introduction.

1:58

So we're just gonna get right to it. Um, so a little bit about the format.

2:02

We're gonna show you a, um, indicative image,

2:07

then we're gonna preview the audience question, uh, show you the case,

2:11

go through a little bit of didactics,

2:13

and then go to an audience poll for the question.

2:17

So the first case we're gonna review is Dr. Gio left node Noter.

2:22

Um, so this is the indicative lesion. Um, and,

2:27

um, think about it and we'll discuss it here shortly.

2:30

And this is the audience question that I want you all to think about, um,

2:34

as we do the presentation. So, node sub displays the longest choline muscle,

2:39

how A, there's no displacement, B anteriorly, C posteriorly,

2:43

or d I don't know. So, um,

2:48

let me show the image. So this is a patient that came to us, um,

2:53

with, uh, difficulty swallowing and some, um, dysphagia.

2:57

And you can see that there is this, uh,

2:59

reen enhancing lesions centrally necrotic, uh,

3:03

located at the lateral retropharyngeal space and extending into the, uh,

3:07

per pharyngeal space. You can see the normal pharyngeal space on, uh,

3:11

the contralateral sides here, and you can see how small it is on the other side.

3:15

There is mass effect, uh,

3:17

on the mucosal space and the oropharynx here. Um,

3:22

and this is a tors to baris.

3:24

This is a fosil or you can see how there's mass effect from that lesion as well.

3:30

Now the is, and um, I just have the component or the associated, uh,

3:35

pet CT image, uh, for you to see that it was, uh, abnormally,

3:39

metabolically active. Right? Um, so the reason I wanted to,

3:44

um, discuss this area of the, um,

3:48

of the, um, super hyoid neck, um,

3:51

is that it is an area that is very difficult for the clinicians to see.

3:56

So just a little bit of history on the name of the not revia.

3:59

So Henry Revia was an atomic, uh, anatomy professor in France. Um,

4:04

he actually wrote a very extensive book on, uh, human lymphatic system.

4:07

And all the lymphatic levels that we utilize today actually arises from this

4:12

work, and it is due to him that we give it this name.

4:17

So the nodal ruber is located in the lateral, uh, retropharyngeal space,

4:22

and it is located anterior to the long colline muscle.

4:25

They extend from the C one C two level to the level the OID bone.

4:29

As you can see, um, usually the size is very, very small, three to five,

4:34

uh, millimeters. And I don't know if you call that we measured that, um,

4:38

nodal vie air, and it was 2.7 centimeters. So clearly very, very abnormal.

4:44

Um, the reason this is so important to, uh,

4:47

keep in mind when you are evaluating head and neck tumors in the super hyoid

4:52

neck is that these notes are absolutely not detectable,

4:56

not palpable on clinical evaluation,

4:58

even when they're enlarged as the patient that I just showed you. And, um,

5:03

if the clinician doesn't know about it,

5:04

they cannot treat it and it can be a source, um, o of course,

5:09

of residual tumor, uh, resulting in much worse prognosis for the patient,

5:15

um, uh, which actually has been proven in the literature.

5:18

So if we don't tell the clinicians that this notice there,

5:22

they're not gonna treat it, and the, uh,

5:23

patient outcome is gonna be much poorer. Um,

5:26

so please make sure that you look at these, uh, notes in your evaluation.

5:31

So just a brief, um, anatomy review. So, um,

5:35

this is an m r i neck axial T two weighted sequence.

5:40

We can see that the feral space is located posterior to the, um,

5:45

pharynx is here located in this, uh, blue line,

5:49

our longest coline muscles, um,

5:51

which are located posterior to the retro pharyngeal space. And then we have, uh,

5:55

this fat line here and tear to the vertebral body, which is the, um,

6:01

prevertebral space.

6:02

And then lateral to the monga colline muscle is where we have the lateral retro

6:06

pharyngeal space where the nose, uh, live. So I want you to,

6:11

uh, see that if you have, um, a big mass here, right,

6:15

located in the lateral pharyngeal space, that's gonna move the, um,

6:18

longus coline muscles, uh, posteriorly. And that's an indication that,

6:23

uh, you know, also you have a lesion in this space. Now,

6:28

um, this has nothing to do with the no of reve,

6:31

but the longus coline muscles are very important in this region of the neck.

6:35

If they're, uh, uh, you know, displaced posteriorly,

6:38

then you must have a mass anteriorly in the retropharyngeal space and the

6:42

muscles are moved anteriorly,

6:44

then you must have a lesion in the vert row space. Um,

6:49

so the longest colline muscles are a great anatomical marker for location of

6:54

lesions within, uh, the neck, uh, deep spaces.

6:59

So the retropharyngeal space, um, as I mentioned already,

7:04

you must evaluate the longest colline muscles to know, uh, where the, um,

7:08

you know, lesions are located. Uh,

7:11

know that the retropharyngeal space spans from the base of the skull base to the

7:16

mediastinum. Um, as we have mentioned already,

7:20

it is anterior to the vertebral muscles and posterior to the phn and esophagus.

7:24

And this is also important to understand that it's not a single space,

7:27

it's actually a double space with two components,

7:31

the true retropharyngeal space and the danger space.

7:34

And so this is what we're talking about. Okay,

7:36

so you have the anterior retropharyngeal space, which terminates at C seven.

7:41

Uh, this space will not extend into the mediastinum and will not result in, um,

7:47

mediastinitis, whereas danger space is posterior to the, uh,

7:51

retropharyngeal space. Allah,

7:53

it extends past the C seven vertebral body into the mediastinum and can

7:58

cause, uh, severe mediastinitis and other, uh, problems. So this is also a, um,

8:03

source of spread of, um, metastatic disease. Okay, Ashley,

8:07

you wanna run the, uh, audience response. So notice the er,

8:11

what happens with the long longest colline muscles.

8:17

Okay, so let's show the audience response. Okay, good.

8:22

So most of you got the, uh, correct answer,

8:24

which is that they're displaced posteriorly. Okay.

8:29

And then I'm gonna stop sharing. So Dr. Alday can, um, start with case two.

8:35

So we'll turn our attention to the carotid space, uh, next. Uh, and, uh,

8:39

we'll start by showing a representative image of a lesion within the carotid

8:42

space. So you can start thinking about it in, uh, in the meantime. Uh,

8:47

the question is, which, uh,

8:49

which of the following cranial nerves is not considered part of the supra oid

8:53

carotid space? Creon, F 7, 9, 10, 11, or 12?

8:59

So, as I look at the carotid space, the way I like to think about it is,

9:03

and in general and head and neck lesions is placing the lesion in a space and

9:08

then looking on m r i on the signal vascularity and what it's doing to the

9:12

surrounding structures. So when I look at this image here, what I see is, uh,

9:17

a lesion situated in the carotid space that is T two hyperintense,

9:21

and I'm seeing that lesion displacing the, uh,

9:25

internal carotid artery anteriorly. And on T two,

9:28

I do see a lot of what looks like flow voids, uh,

9:31

or T two hypo intensity within the lesion. So

9:39

I'm gonna, uh, ask you a couple of questions here. One is,

9:42

what do you think is the leading differential diagnosis to, to think of? And,

9:46

uh, number two, how many lesions do you guys see on the M R I? Uh, and then you,

9:50

you can write that in the chat if you, if you'd like to,

9:56

I can show you the pet right now. Uh, and as you know,

10:00

we're looking at the pet, the one,

10:02

the first question I want you to think of is what radiotracer we're using here,

10:06

and how can I tell that? And then, uh,

10:08

obviously the other question is how many lesions are present?

10:13

So one thing, you know, when I look at radio tracers, and this is, uh,

10:17

dotatate or somatostatin, uh, receptor,

10:20

which is predominantly used for neuroendocrine tumors,

10:23

including this entity here to differentiate between it and between another

10:26

common entity in the carotid space, normally physiological uptake. Uh,

10:31

and the reason why I can tell that it is,

10:32

is very strong in the pituitary and a variable degree of uptake in the carotid

10:37

or ciliary tissues. And the thyroid, which tend to be generally moderate,

10:41

but can be intense. And I see a very intense uptake in two areas.

10:45

And this is the, uh, uh, the bilateral carotid spaces.

10:48

And this is the benefit of using, uh, the dotatate pet.

10:52

'cause the smaller lesions sometimes can be challenging on M R I. And as,

10:56

as you see here, it might be hard to see on the T two. And even when I, uh,

11:00

look at the post contrast,

11:02

the con lesion might be hard to pick and can be easily missed. So the, uh,

11:06

PET gave give us the benefit of, uh,

11:08

detecting those lesions in addition to allowing us to differentiate between it

11:12

and other common entities, which we'll discuss shortly. The other thing I, uh,

11:17

always wanna discuss with the carotid space is location, uh,

11:21

can help us sometimes predict not only the pathology,

11:25

but potentially which, uh, component of the carotid space. So again,

11:29

as I'm looking here, I can see if significantly artily enhancing lesion,

11:34

uh, with respect to the muscles.

11:36

And I see the internal carotid artery being displaced anteriorly on the

11:40

contralateral side at the bifurcation of the carotid,

11:43

I see a lesion sitting and, uh,

11:45

not quite splaying the internal and external carotid arteries, but, uh,

11:49

given its size, but it's sitting there at the bifurcation,

11:52

and you can appreciate that very nicely on the sagittal images

11:58

with the bifurcation. Okay, so turning our attention into the, uh,

12:03

dis discussion of the, uh, carotid space before we move on.

12:07

So it's always important to talk about anatomy and boundaries when we're coming

12:10

up with a differential diagnosis.

12:12

So the carotid space itself is a cylindrical space that extends from the jugular

12:16

foramen to the thoracic inlet,

12:18

and it's divided superior and inferiorly by the hyoid bone.

12:22

And today we're turning our attention to the supra hyoid carotid.

12:25

Its contents are in the supra hyoid neck that the crown jewel of it is the

12:30

internal carotid artery. Uh,

12:32

and it's located medial and slightly more anterior to the internal jugular vein.

12:37

Uh, and those are the two prominent vascular lesions.

12:40

And it contains four cranial nerves in the supra hyoid neck. Uh,

12:44

there is variability of location of the nerves based on anatomical cad

12:49

resections, but this is the most common appearance.

12:51

Cranial nerve nine typically is anterior situated between the two vessels.

12:56

Cranial nerve 12 is typically medial posterior to the carotid, and, uh,

13:00

10 and 11 are more posterior with a variable location.

13:03

And then along the posterior sheet there is the sympathetic trunk and

13:08

anteriorly there is the, an cervical, which, uh,

13:12

forms from C one C two and C two C three nerves and supplies the infra hyoid,

13:17

uh, mus, uh, infra hyoid muscles. So based on the internal contents, you know,

13:22

hence the differential for lesions can be formed, uh, with, with, uh,

13:26

with respect to the, the space. So the, so the margins anteriorly, uh,

13:31

anterior to the carotid, uh,

13:33

there is masticator and per pharyngeal space medially,

13:37

there is the retropharyngeal space that Dr. Guzman discussed laterally.

13:41

There's a parus space, which we'll discuss subsequently and posteriorly,

13:44

there is the paravertebral muscles, uh, and their, uh,

13:49

their com uh, components. So speaking about the differential diagnosis,

13:54

uh, this lesion is, uh, paraganglioma. And, uh,

13:57

talking a little bit about paragangliomas of the head and neck,

14:00

they're typically rare entities of tumors in the head and neck and constitute,

14:04

uh, a little bit more than 0.5%. Now, unlike a lot of other areas in the body,

14:09

they're predominantly parasympathetic. 'cause as you know,

14:11

paragangliomas can be sympathetic and parasympathetic.

14:13

The sympathetic typically secrete the catacholamines.

14:16

The parasympathetic typically do not, and these typically do not secrete, uh,

14:21

the most common of them is the carotid body tumor constitute about 60%.

14:25

In 25% of the cases such as this case, they can be multicenter.

14:29

And the majority of the time, if they are,

14:31

they're typically related to a syndrome or familial. Um,

14:35

one important thing to understand when it comes to syndromes,

14:38

the ate dehydrogenase mutation is at the center of the majority of these

14:42

syndromes, and there's multitude of genes that contribute to it.

14:45

And there's multitude of paraganglioma syndromes associated with this.

14:48

I sh the case that I showed you right now is a, uh, paraganglioma,

14:54

uh, syndrome, familial syndrome one, and then one in three, for example,

14:58

have a high propensity to be present the paragangliomas in the neck.

15:01

Another syndrome that's associated with it is carish triad,

15:05

where you have just tumors, uh,

15:07

lung chos and you have paragangliomas. And in fact, you know,

15:11

I've seen one last couple of weeks, m e m type two NF and, uh,

15:15

one and von Hippa Linda are other things.

15:17

So when you see multiple paragangliomas of the head and neck,

15:20

those are things you want to think of in terms of, of imaging. Again, as I,

15:24

you know,

15:24

going back to the anatomy location and help you predict which nerve it is.

15:29

So the carotid body tumor is the one that displays the I E C A

15:34

and i c a and sits in between 'em as, as I showed you in that image.

15:38

The Glo panicum, uh, tumor, uh, tumors are, you know,

15:42

sit at the cochlear promontory and we're not talking about them. Uh,

15:45

today at the skull base arise from cranial nerve nine.

15:49

And then the jugular typa,

15:51

or more jugular in the jugular vein arises from cranial nerve 10.

15:54

And CLOs vali are the ones that most commonly are located between the jugular

15:59

foramen, you know, and the supra hyoid neck.

16:00

They have propensity to be located at the lateral ma uh,

16:05

mass of C one,

16:06

because the majority of them arises from ganglion nado at that level.

16:10

And the case I showed you is one of those. Uh, and then given their location,

16:14

when you think about it, cranial nerve 10, where it's located,

16:17

as we talk about it here,

16:19

that location is gonna push the vessel 'cause it sits behind the internal

16:24

carotid artery, is gonna push it anteriorly.

16:26

So that's one clue for you to determine the origin or which nerve is, is,

16:31

is the responsible for para paraganglioma. And lastly,

16:34

in especially in familial symptoms,

16:36

you can have laryngeal paragangliomas that arise from the laryngeal per ganglia.

16:39

And in there, typically located in the visceral space,

16:42

similar to other paragangliomas,

16:44

they're arterially enhancing and they do not look like mucosal lesions.

16:48

They're typically submucosal. And you know, so they're, they're,

16:51

you are looking at them, you're like, it doesn't look like a carcinoma.

16:54

So you see an arterially enhancing lesion in, you know,

16:56

the larynx that is not related to the mucosa.

16:59

One of the things to think about is definitely paragangliomas and syndromic

17:03

paragangliomas. In fact, I've seen one last week.

17:06

So very quickly in terms of imaging on ultrasound,

17:09

this is ultrasound they did a couple of days ago for a different patient. Uh,

17:13

they tend to be hypo coic. Again,

17:15

they're very intimate relationship with the vessels given their, uh,

17:19

location in the carotid space. And, uh, they are very vascular,

17:24

such as this case. This is the ultrasound, and this is the companion ct.

17:28

You can see the internal external, uh, carotid arteries. You can see, uh,

17:31

a lesion displaying them and significantly vascular.

17:34

And this is its appearance on the ct, on sagittal images on m r I,

17:39

they're typically T two hyperintense, the flow voids on T two.

17:42

And then on T one you can have the hyperintensity, which is reflective of,

17:46

you know, slow flow within the vessels or, uh, uh, turbulent flow. And it's, uh,

17:51

two things that, uh, I wanna emphasize is one,

17:54

the significance of of not doing a biopsy on these, uh,

17:59

'cause we perform biopsies.

18:00

So not doing a biopsy and being mindful of thinking about that differential and

18:04

angiogram for treatment planning. Uh,

18:06

most common differential would be a nerve sheet tumor and give,

18:10

they're typically given, uh, they're, they're arising from, you know, you know,

18:14

the nerves they're displayed, they tend to displace the, uh,

18:17

vessels anteriorly or, uh, medially the carotid. And then additional, uh,

18:21

lesions always because of the vessels, the vascular,

18:23

and there's a whole gamut of it that's hard for us to go through. Uh,

18:27

which include dissection, FERBs aneurysm, pseudo aneurysm, carotid blowout,

18:31

F M D, vasculitis, uh, and then nia or face syndrome or typic syndrome,

18:36

multiple names for it. And then always remember lymph nodes, uh,

18:39

whether it's infection met or lymphoma. Uh,

18:42

a couple of common lesions I wanted to talk very quickly about.

18:45

This is a carotid space, schwannoma. And, uh, things that, uh, you know,

18:50

typical appearance of schwannoma is, you know, typically T two hyperintense,

18:53

but different, uh, appearance based on the content. And as you can see here,

18:57

it's displacing the carotid laterally. Uh, and then on, uh, doted eight pet,

19:01

it doesn't demonstrate increased uptake.

19:03

And that's one way you can differentiate if you're not sure between car, uh,

19:06

schwannomas and paragangliomas. Other thing I want to really, uh,

19:09

talk about very quickly before we, uh, wrap up the car,

19:12

the carotid space is carotid blood. Because, you know, in, in my my practice,

19:17

I do see quite a decent amount of these, so I want to touch base with it.

19:20

'cause I know not a lot of people see him much.

19:22

Carotid blowout is a potential risk for treatment of head and neck cancer,

19:26

seen in about three to 5% of patients that have, you know, uh,

19:30

surgery and up to 10% with people that have radiation. Uh, and then the, uh,

19:35

what, what happens is it, it's,

19:38

there's an effect on the vessel that increases the risk of the vessel to bleed

19:42

and is classified as, uh, threatened where we see abnormal imaging of vessel,

19:47

whether, whether it's, you know, changing in caliber of pseudo aneurysm, uh, or,

19:51

you know, stenosis, uh, or it can be imminent or, you know, uh,

19:55

active where you see active bleeding or blush on your arterial face.

20:00

Things that increase the risk of it is location of tumor with respect to the

20:03

vessel, if it's encasing the vessel, uh,

20:05

narrowing changing caliber of pseudo aneurysm, uh, or, you know,

20:09

obviously active bleeding.

20:10

And one big thing that it seems to be more sensitive is necrotic tissue

20:15

extending toward the vessel.

20:16

This is a patient that had had the neck cancer that was treated with, uh,

20:19

radiation and surgery,

20:22

and you can see the necrotic tissue and ulceration from radiation.

20:25

And some of the E C A branches, you can see here the caliber of the vessels.

20:29

So I'm going Coggle to cranial, there's significant narrowing of two vessels,

20:33

two branches, this is a.here, and then that increases its caliber,

20:37

and then it's, you know, that's the normal caliber of the vessels.

20:40

You can see that change, uh, change in caliber. This patient came in with, uh,

20:44

uh, active bleeding at the time, time, uh, and had to have, uh, a, uh,

20:49

a stent placement. So that's, uh, pretty much, you know,

20:52

the carotid space and some of its differential diagnosis.

20:55

And then going back to the audience question, Ashley,

20:58

if you wanna ask us the response?

21:03

Yep, Dr. Yep. Perfectly, uh, correct. Seems like everyone you know was,

21:07

was on board on that. Yep.

21:11

So case three, um,

21:13

is the tibular trigone extending to the perennial space.

21:18

So this is a key image. Um,

21:20

and you can see that there's a large mass here on the right side causing

21:25

mass effect on the, um, oropharynx.

21:28

So the audience question for you guys to ponder while we do the presentation,

21:33

displacement of the peripheral andal, uh,

21:35

fat medially and posteriorly means the primary tumor originates in which space?

21:39

A masticator space B parotid space C uh, pharyngeal mucosa,

21:44

dec carotid space, or E um, I don't know.

21:49

So the, um, retro mandibular trigone is actually part of the oropharynx.

21:54

However, it can have extension into the peripheral NAL space,

21:57

which is located in the supra hyoid, um, neck.

22:01

And this is an MR image with normal anatomy.

22:04

So the retro mandibular trigone in parallel to the, uh,

22:09

nodal ruber cannot necessarily be palpated by the, uh,

22:14

E N T clinician or the referring clinician. Um, it is located in this, uh,

22:19

little space of fat here, um, between, uh, the, uh,

22:23

teeth and the body of the mandible. Uh,

22:27

this is the base of tongue here, and these are domesticated muscles. And again,

22:31

it's very important, uh, for us to look at this region in our anatomical images,

22:36

because if we don't talk about it, uh, lesions in this region can, uh,

22:40

go undiagnosed, uh, which causes, uh, poor prognosis.

22:47

So, uh, the retro mandibular, uh, trigone, again,

22:50

is a subside of the oral cavity, um,

22:53

which consists of the mucosa posterior to the last mandibular molar. Um,

22:57

because of its, its location,

22:59

it has a propensity to extend into the peripheral andal space,

23:02

which is part of the super hyoid neck. And like I just mentioned already,

23:07

if you take nothing else of this, of this entire presentation today, study,

23:12

you know,

23:12

retropharyngeal lymph nodes and the retro mandibular trigone cannot be palpated

23:17

appropriately by the clinician. And if we don't mention it,

23:21

it's gonna go undiagnosed, uh, by the referring clinician, and of course,

23:25

result in much worse prognosis for the patient.

23:30

So, um, again, a brief review of anatomy. Again, this is an Mr.

23:35

Axial image of the neck at the level of the, um,

23:39

retro mandibular ular trigone and the paranal space. Um,

23:45

T two weighted imaging, which we can tell by the bright C s F.

23:48

So the masticator space, uh, here in red, um,

23:51

contains the masticator muscles, um, uh, the masseter muscles,

23:56

the regrade muscles, and the temporalis muscles. Of course,

23:58

we have the parotid space, which contains the parotid mass.

24:02

We have the mucosal space here. Again,

24:05

the longus colline muscle is such an important, uh,

24:08

imaging anatomical marker for us in the head and neck. Um,

24:11

so try to become familiar with it and lateral to the longus colline muscle and

24:16

medial to the ator spaces where we have the paranal space. Uh,

24:21

similar to the carotid space, it is, um, separated, uh, in, uh,

24:26

by the styloid processing to the pre, uh, uh,

24:29

styloid peral space and the post, uh, styloid, uh, peral space.

24:35

So the contents of the per Ange space will be discussed in the next case by Dr.

24:40

Aya.

24:41

It is important to understand what the boundaries of the paral space are.

24:46

So again, as I mentioned before, uh,

24:48

laterally we ha laterally and anteriorly. We have domesticate space,

24:53

uh, laterally and posteriorly.

24:55

We have the deep lobe of the paric land with the, uh,

24:59

retro mandibular vein, uh, located here, uh, posteriorly.

25:04

We have the, uh, styloid, uh, process as well as the, uh,

25:09

tensor molecular styloid fascia, which is this, uh, pipeline that, uh,

25:14

we see here. Um, and anteriorly, we have, of course, the, um,

25:19

uh, uh, the tego mandibular rae, uh, that extends from the medial,

25:24

uh, tego plate, um, to the mylohyoid line. Now,

25:28

why is it important to understand, um, all of these, um,

25:33

kind of boundaries for the per pharyngeal space? So,

25:35

similar to the longest colline muscle,

25:38

depending on where the tumor is located,

25:42

that perineal space fat is gonna be displaced.

25:46

So if you have, uh, pharyngeal mucosal lesion,

25:50

which is located anterior and medial to the perge space,

25:54

that per pharyngeal fat is gonna be displaced posteriorly and

25:59

laterally. If you have a masticator, um,

26:03

space mass,

26:04

which is located anterior and lateral to the per pharyngeal space,

26:08

you're gonna have medial and posterior displacement of the per

26:13

a**l, um, fat. If you have a mass in the parotid space,

26:18

which again we mentioned is in the lateral and posterior aspect of the per

26:22

pharyngeal space,

26:23

that's gonna move your peripheral a**l fat anteriorly and medially.

26:30

And finally, if you have a carotid space tumor, which is located, uh,

26:34

posterior and medial to the peral, uh, fat,

26:38

that peral space is gonna be displaced anteriorly and

26:43

laterally, just like the longest colline muscles.

26:46

Understanding this anatomical relation between the peroneal space and

26:51

the spaces surrounded,

26:53

it is critical to understand where the iso center of your lesion is.

26:58

Uh, and I highly encourage you, uh, to all to practice, um,

27:03

locating masses by looking at the displacement of the peroneal, uh, uh,

27:08

space fat. Okay, Ashley, so audience response now,

27:13

displacement of the peroneal fat mely and means the tumor

27:18

originates in which space.

27:24

Okay, great. So most of you got the correct space, which is masticator space.

27:28

Perfect. Okay, on to the next case then.

27:33

Okay. So moving on. Uh, we, uh,

27:36

this is a nice segue to the per pharyngeal space representative image. Uh,

27:40

m r i facet T two. And our, uh, audio question is,

27:45

uh, which of the following is not a content of the peral space,

27:49

fat lymph nodes, uh, uh,

27:52

V three branches of the trigeminal nerve or, uh, ciliary tissue. Uh,

27:57

and as we're thinking of this, we'll start discussing the case, uh, and again,

28:00

you know, similar to what Dr. Guzman have said before,

28:04

always location of the epicenter of the mass, and then from there,

28:07

the differential diagnosis, uh, of the lesion.

28:10

So I'm looking at a lesion here that is in the supra hyoid neck,

28:14

and it looks like it's predominantly situated in the per pharyngeal space,

28:17

comparing to the other side where the fat is suppressed and it's not, uh,

28:21

outside of a little bit of mass effect on the, uh, medial intergrade muscle,

28:24

it's not doing a whole lot of displacement.

28:26

So I know more likely than none that the,

28:29

the space is intact and it's most likely coming from the space. Uh, it is very,

28:33

uh, T two hyper intense and on post contrast sequence,

28:37

it demonstrates, uh, significant, uh, enhancement, uh,

28:41

to bits and portions of it while other par parts are not enhancing. Uh,

28:45

and then my lead differential when I see a lesion like this in the per

28:48

pharyngeal space is gonna be either a, uh, salivary, uh,

28:53

gland or salivary tissue, uh, primary lesion or a, uh,

28:57

neurogenic lesion, just knowing what, which, which of the two are,

29:00

are the most common.

29:02

And then based on the imaging appearance and the significant, uh,

29:05

T two hyperintensity hyper, you know, I would favor, uh, something like, uh,

29:09

benign mixed cell tumor or pleomorphic adenoma as the primary lesion would,

29:13

would the back of my mind thinking of something of schwannoma as the less likely

29:17

consideration given the appearance on, on the sequences. So moving forward,

29:22

you know, again, think about the differential. Uh,

29:25

let's talk a little bit about the anatomy, uh, contents and, and,

29:27

and boundaries. And I know Dr. Guzman talked about a little bit of boundaries,

29:30

so we'll, we'll skip that and just talk predominantly about the contents.

29:34

The majority of the spaces made of fat. Uh, it does have, uh,

29:38

to a variable degree, variable vessels from, uh, the external carotid, uh,

29:43

artery branches. Uh, and then from the tego venous plexus, again,

29:47

there's variability of how much vessels, if any,

29:49

are present based on the variable anatomy, but typically more likely than none,

29:53

there is, and there is branches of V three in particular supplying the, uh,

29:57

tensor valley palatini muscle and ciliary tissue.

30:00

And there's always a debate if, if the primary is, uh, ciliary,

30:05

is it truly from a, uh, you know,

30:07

minor ciliary tissue in the periphery andal space,

30:10

or is it exo coming from the deep lobe of the adjacent parotid?

30:14

And sometimes it is really hard to say. Sometimes it might be easy as Dr.

30:18

Uh Guzman said,

30:19

based on the displacement of the space or if there's residual space. Um,

30:23

in terms of the lesions of per perianal, the majority of the lesions are benign,

30:28

uh, 75 to 85%. Uh,

30:30

it does not constitute much of the primary head and neck tumors. As you know,

30:34

0.5% of all of the primary head and neck tumors arise in the per pharyngeal

30:38

space.

30:39

The most common primary of the perianal space is gonna be salivary gland, uh,

30:44

followed by neurogenic, uh, of the salivary.

30:47

The most common is benign mixed cell tumor or pleomorphic adenoma.

30:51

And of the neurogenic, uh, paraganglioma, typically from, uh,

30:55

vagal nerve branches, followed by schwannoma. And then,

30:58

given that the majority of the, uh, of the content is, is fat,

31:02

there's always, you know, a possibility of lipoma or lipos sarcoma.

31:06

And certainly infection spread from adjacent spaces is another consideration.

31:12

So when talking about differential, as we spoke earlier,

31:15

this is a paraganglioma. The reason why I think it's paraganglioma,

31:19

and you can see the contralateral fat,

31:20

predominantly fat and small vessels in the space,

31:24

is that it's, uh, significantly enhancing.

31:27

And I can see increased vascularity along the margins.

31:30

So I would favor paraganglioma schwannomas. You know, we have, uh,

31:35

variable signal,

31:35

but typically they're T two hyperintense and they demonstrate a degree of

31:40

enhancement. Uh, they are usually on CT hypo intense to the muscle.

31:45

So when I'm looking at a lesion like this,

31:47

I am thinking it's not gonna be paraganglioma because it's not significantly

31:50

enhancing on ct. And then on T two,

31:53

the typical appearance of a benign mixed cell tumor is, you know,

31:57

more bright or more T two hyperintense. So I'm thinking, you know,

32:01

it's probably not gonna be an I would lead with schwannoma in, in this instance.

32:05

Uh, and then, you know, every now and then you'll see one of,

32:08

one of these lesions here. This is the perineal space on, on the left,

32:12

and you can see the right, again, predominantly fat.

32:14

And you can see that this lesion, there is expansion, uh, of the,

32:18

of the perineal space. And there is, you know, fat content and heterogeneous,

32:22

uh, tissue inside of it. So this would be, you know, a fat, fat lesion.

32:27

And certainly if you have an M R I, you can confirm it with, with the fat,

32:30

fat sequences. And I would, you know, given that I do see soft tissue,

32:34

I would favor that this would be a little bit more aggressive than lipoma,

32:37

possibly a lipo sarcoma, which was the case on, uh, this case.

32:41

And then this is another case, you know, more common in pediatrics,

32:44

but you tend to occasionally see it in adults.

32:46

This actually case I read last week is a patient, uh,

32:50

30 years old that came in with, you know, uh,

32:52

difficulty breathing and swallowing. And you can see a T two, uh,

32:56

hyper intense mass, predominantly situated in the per pharyngeal space,

33:01

but it does extend to the pharyngeal, uh, walls and compresses the pharyngeal,

33:05

uh, uh, the nasal pharyngeal airway at the same time, you know,

33:09

it is at the margin of the deep lobe of the parotid, but notice this is not,

33:12

you know, uh, doing a lot of mass displacement. It's, you know,

33:16

kind of spacial and embedding into the spaces.

33:19

So if you look a little bit closer, there's also another component in the, uh,

33:23

retro ular space. So when I was reading this with one of our fellows,

33:26

there were, you know, the thought process was, could this be a, uh, uh, pre,

33:30

you know, again, with the differential, could this be a, uh, a, a,

33:33

a schwan or could the, is this be benign mixed cell tumor,

33:37

or could this be pleomorphic, uh, uh, adenoma, or could this be, uh,

33:41

something like a paraganglioma? And then this is the dotatate pet,

33:45

and there's no increased signal. But if you look closely,

33:47

you can see some calcifications in the ocular component or separate lesion.

33:52

And we thought that this is a low flow vascular lesion,

33:55

which ended up being the case. Now, these are more common in,

33:58

in younger patients in the per pharyngeal space,

34:00

but you do see 'em every now and then in the, uh, adults.

34:02

So going back to our audience question to, to, to recap, uh, you know,

34:07

the, the space,

34:08

which of the following is not a content of the per pharyngeal space?

34:14

Okay? And, and then the majority of, uh, if you got it right, yes. Remember,

34:19

you know, there are a few, uh, typically V three branches in particular, uh,

34:24

the, uh, you know, branches, uh, supplying deten vini. And then, and,

34:28

and then hence why you will have nerve, uh, you will have, uh,

34:30

neurogenic tumors like, uh, paraag, gliomas and schwannomas.

34:34

And then the other thing when it comes to, uh, ciliary tissue, again, you know,

34:39

there, you know, potentially debatable,

34:41

is the ciliary or the most common tumor being the benign mixed cell tumor,

34:44

is it arising actually from the perineal space or the deep lobe? And,

34:48

and there is definitely perineal, uh, uh, perineal space,

34:53

manous delivery gland. Typically, there's no lymph nodes in the space. Okay.

34:57

And then with that, moving on to Dr. Guzman,

35:02

Our next case is a parotid mass with perineal spread of disease. Um,

35:07

as hopefully most of you know, uh,

35:09

per capita adeno cystic carcinoma is the tumor with the highest rate of

35:14

peral spread of disease. Although in, um, in brute numbers,

35:19

it is squamous cell carcinoma,

35:20

just because it is so much more common than adeno cystic carcinoma. And, uh,

35:25

these are the, uh, key images. So now I'm going to, uh, go to the case.

35:31

All right, so this is a person that presented with a parotid space mass.

35:36

Um, this is a flare, uh, sequence,

35:39

and you can see that there's significant enlargement of the entire, uh, gland.

35:44

Remember that to differentiate between the superficial and the deep lo the

35:48

parotid, you need to use the retro mandibular vein.

35:51

This is important because the, uh,

35:53

cranial nerve seven runs in the deep space of the parotid lobe.

35:57

And when the surgeon is, uh, operating, they need to know, um,

36:02

if they're gonna have to go into the deep space of the parotid gland as, uh,

36:06

they're at risk of course, of injuring the nerve. As you can see,

36:10

there's significant restricted diffusion along the entire parotid gland,

36:16

uh, which is, uh, very abnormal. Um, 70% of parotid, um,

36:21

mass lesions tend to be benign pleomorphic adenomas. And, um, they don't, uh,

36:26

show this, um, significant increased restriction, um, again,

36:30

accompanied by, uh, low a d c values,

36:33

which is compatible not with T two shine through,

36:36

but with actual true restriction. We can see that there's a lot of, um,

36:41

vascularity in this lesion. Um,

36:44

and then there's cord like and enlargement of the auricular temporal nerve here,

36:48

right? So this is the normal, uh, IC gland, which tends to be fatty,

36:53

somewhat bright, um, both on T one and T two weighted sequences.

36:57

But you can see that there's this kind of cord like, uh,

37:00

lesion along what the course of the auricular temporal nervous, uh, which is,

37:05

uh, clearly abnormal. Then as we move, uh, onto our,

37:10

uh, enhanced images, um,

37:14

we can see the same kind of appearance, right?

37:16

So we have a significantly enlarged, uh, parotid, uh, gland,

37:20

both the superficial and the deep lobe. Again,

37:23

you have to find that retro mandibular vein to separate both.

37:27

And you can see this cord like thickening, uh, uh,

37:31

an abnormality of the auricular temporal nerve, um, which, uh,

37:36

of course is suggestive of, uh,

37:38

auricular temporal nerve invasion and peroneal spread of disease.

37:44

Um, in fact, this patient, um, when they went, uh,

37:48

to pathology, uh, after resection, uh,

37:51

it was confirmed on pathological evaluation that they did have perineural spread

37:56

of disease, and that the, um, tumor was in fact an adeno cystic, uh,

38:01

carcinoma, which, um, was suspected based on the perineural, uh,

38:05

appearance. So, for the audience question, things to think about,

38:10

um, as I do the presentation, um,

38:13

the UROP temporal nerve is in which perineural, uh, spread highway,

38:18

uh, corneal nerve, uh, six to seven, five to seven,

38:23

eight to seven, I don't know.

38:28

So this is critical in the evaluation of perineal spread of

38:32

disease, especially if you're dealing with superficial lesions to the parotid.

38:37

So it doesn't only have to be a parotid mass, it can be, um, like, uh,

38:41

skin squamous, cell carcinoma, um,

38:44

melanoma or metastatic disease from, um, different, uh,

38:49

uh, metastatic tumors that might affect the face, because we have, uh,

38:54

two different large nerves that, uh, live in that area.

38:57

Sorano nerve five and chrono nerve seven.

38:59

And you can see that there are areas where they interact with each other, right,

39:04

where they, um, mix with each other.

39:06

The most common one being this auricular temporal nerve, which is,

39:09

is a branch of, um, which is a branch of V five,

39:14

but then it has a connecting branch to the Corda Symphony,

39:17

which is a branch of V seven, uh, with the Corda Symphony living within the, um,

39:22

the deep space of the IC gland. And this is that, uh,

39:26

highway that we see here, uh, when we see it affected in this patient.

39:32

Um, so, uh, this is another case from the literature. Um,

39:38

this is the, um, mandibular, uh, ramus red and the mandibular condyle.

39:44

The, uh, OT temporal nerve runs in a C shape behind, uh,

39:48

this area and connects to V five, right?

39:52

This is the foramen oval. This is foram noval here on the right,

39:57

on the left side, which is, um,

39:58

abnormally en large and enhancing normal on the right side.

40:02

And you can see that there's this cord like thickening and enhancement compared

40:07

to the normal contralateral side. Remember, again, that,

40:11

this or temporal nerve, then we'll connect to the Corda Symphony, uh,

40:16

branch of cranial nerve seven, living in the deep lo of the parotid,

40:20

causing that, uh, cranial nerve five to cranial nerve seven, uh,

40:24

perineural highway, uh, spread of disease. Um,

40:29

this is another example from the literature. Um, this is the same finding,

40:34

but on the other side, right? So, um,

40:38

this is the Anglo basal fascia, which is around the nasopharynx.

40:42

And lateral to that is where we find our, uh, cranial nerve, uh,

40:46

five for amino valley. So this is abnormal for Amino Valley, not enlarged,

40:50

not enhancing. This is abnormal amino valley,

40:54

very enlarged and enhancing with associated cord like

40:58

thickening and enhancement of the orical temporal nerve. Again,

41:03

very concerning for, uh,

41:05

perineural spread of disease and putting the patient at risk of the cranial

41:09

nerve five, right to cranial nerve seven, uh, per, uh,

41:13

perineural spread of disease highway, uh,

41:15

connecting to the Corda Symphony in the deep lobe of the paric gland.

41:21

Now, there are multiple, uh, cranial nerve, five to seven highways.

41:26

Um, so I'll just mention a couple of the more, uh,

41:31

um, um, more prominent ones.

41:34

So hopefully everybody knows that the, uh,

41:37

gr superficial petrosal nerve arises from genic ganglion,

41:42

um, which is the ganglion of cranial nerve, uh, seven.

41:46

And via that lingual nerve, we can have a, um, uh,

41:51

greater superficial petrosal nerve, uh, uh, highway, uh,

41:55

that connects with the, uh, cranial nerve five. Here again,

42:00

we have an abnormal enlarged from valley, which carries, again,

42:04

cranial nerve five, abnormal enhancement of the ness sinus with, uh,

42:08

retrograde, uh, extension through the greater petrosal nerve, uh,

42:13

into the genetically ganglion. Um,

42:18

this is another one, uh, with the, uh,

42:21

tebo palin ganglion connection at V two, um,

42:25

with connection to V seven through the greater superficial petrosal nerve via

42:29

the, uh, uh, the video nerve.

42:32

So hopefully everybody recognizes the structure as the tego palatine

42:36

fossa usually containing fat and some vessels, some nerves.

42:41

But here you can see it's abnormally enlarged, abnormally thickened, uh,

42:46

noting that of course, in the tego palatine fossa,

42:48

we have the branches of V two.

42:50

Then we have retrograde flow through the foramen rotunda, which is the, uh,

42:55

foramen, uh, that carries, uh, c nerve, uh,

43:00

five V two branches back into the, um,

43:04

cabeno sinus. And we see retrograde extension again through that superficial,

43:09

greater superficial petrosal nerve into our geno ganglion with abnormal

43:14

enhancement of both the typa and the labyrinthine section

43:19

of the, uh, facial nerve, uh, cial nerve seven, uh, again,

43:23

demonstrating another cranial nerve five, cranial nerve seven highway,

43:27

this time through V two branches. Alright,

43:32

so we'll do the audience response now.

43:39

Okay, awesome. I am so pleased to see this. Yes. Um,

43:42

definitely the oroc temporal nerve is the, uh,

43:46

cranial nerve five to seven highway, uh, the most important one, although,

43:49

as I mentioned, there's quite a few of them. And with that,

43:53

I'll turn it over to Dr. Alaya.

43:58

So in continuation with Dr.

43:59

Guzman's discussion of perineural spread masticator expense, uh, lends itself,

44:03

you know, really nicely for the next case. So I'm showing you, uh,

44:07

representative image of, uh, someone's 25 years old, and, uh,

44:12

have a, uh, lesion, uh, situated in masticator space.

44:16

Just want you to think what is your, uh, differential? It's always, you know,

44:19

hard with these lesions specifically to come up with a specific diagnosis, but,

44:23

uh, what is, uh, what is your differential to start thinking of? And then, uh,

44:27

the audience question is, which of the following is not a,

44:30

a masticator space muscle, uh, temporalis muscle medial oid,

44:35

uh, the masseter or the vaccinator muscle?

44:40

Okay, so masticator space anatomy is, to me,

44:43

is one of the more fascinating spaces of the supra high neck for a couple of

44:46

reasons. One, uh, it's typically ignored because the pathology is,

44:51

isn't as common as other spaces. Uh,

44:54

number two is there's so many confusing, uh, phrases and so many,

44:59

uh, di uh,

45:00

diversion between surgeons and radiologists in terms of how we define it.

45:04

So I wanted to spend a little bit of time discussing the anatomy,

45:06

the boundaries, and the subspaces before turning our attention to the,

45:09

to the case.

45:10

So starting first by talking about the contents of the masticator space.

45:13

So predominantly the contents are, you know, muscles of mastication,

45:17

which include the lateral, uh, turid muscle, uh, the medial turid muscle,

45:21

the master muscle, and the temporalis muscle. Uh,

45:25

and then there is a small component of the mandibular, uh, bone,

45:29

which includes the posterior body and the ramus. And we also have, uh,

45:34

V three nerves. So in, in keeping with Dr.

45:36

Guzman discussion branches of V three, including for, uh, you know, the, uh, uh,

45:41

V three branches going toward the inferior alveolar canal. And, uh, lastly,

45:47

uh, we have a few vessels, uh,

45:49

also depending on the variation of the anatomy that are branches of the inferior

45:53

alveolar artery vein and oid venous, uh, plexus in terms of, you know,

45:57

terminology in, in, and then you,

45:59

and how we divide it for radiology standpoint. Historically,

46:03

we've divided the space with respect to the, uh, to the, uh,

46:09

uh, zygomatic arch into supra zygomatic space and, uh, you know,

46:13

infra zygomatic space.

46:14

And the supra zygomatic essentially predominantly contains the temporalis

46:19

muscle,

46:19

which is equivalent to what the surgeons typically call the temporal fossa.

46:23

And to the surgeons.

46:24

The temporal fossa is essentially that superior extension of the ma, uh,

46:28

masada space, or the zygomatic masada space,

46:31

and is further divided surgically into potential spaces of superficial

46:36

temporal fossa between the fascia and the muscle,

46:38

and the deep between the muscle and the temporal bone. In terms of the infra,

46:43

uh, zygomatic space, it's, you know, further divided into spaces or, uh,

46:48

sub spaces in the, in our literature historically as, uh, one of the,

46:52

is the mass, uh,

46:53

mass esoteric or sub esoteric space between the master muscle and the mandible.

46:58

Uh, and then we have the, uh,

47:01

tego mandibular space between the medial tego and the, uh, and,

47:05

and the bone, the mandibular bone. And that, uh, essentially, uh,

47:10

uh, corresponds to, you know, the,

47:12

the surgeons basically calling it the infra zygomatic or the pharyngeal

47:16

component of the, uh, of the masticator space. Lastly,

47:20

and to add to the confusion, you hear people sometimes using the phrase,

47:24

the infra temporal fossa or space,

47:26

which is the part of the masticator space that is immediately inferior to the

47:31

skull base. Uh, and then it extends from the pharyngeal wall toward the muscle.

47:36

So those are, and then it's posterior to the, uh,

47:38

posterior wall of the posterior lateral wall of the maxillary signs.

47:41

So those are different terminologies of the space that you might hear people,

47:45

uh, speak of all the time. With that, you know,

47:48

I wanted to switch the order a little bit here, because I, when I go to,

47:51

to discuss the image, I, I wanted to, uh,

47:54

to have that abide as we're looking at this.

47:56

So what I'm seeing here is I'm seeing a T two hyperintense lesion that is

48:01

extending essentially, uh, from the, uh,

48:04

masseter muscle to the temporalis muscle, or in other words,

48:08

extending from the infra, uh, zygomatic, uh,

48:13

masticator space to the, uh,

48:15

suppress zygomatic masticator space that is demonstrating enhancement. Uh,

48:20

and then when I'm starting to think about this from a differential standpoint,

48:23

I, you know, my first feeling is that this is a lesion that is situated in the,

48:27

um, masticated space. Predominantly it's not extending from outside.

48:31

Then I start to work my differential based on the contents of the and location.

48:36

And for me, the overall appearance makes me want to lean toward, you know,

48:40

a primary sarcoma, this lesion here. Now again,

48:43

telling the subtypes of sarcoma might be challenging, uh,

48:47

because they tend to overlap in imaging, with the exception of few of them,

48:50

obviously, the osseous or the, uh, fat containing, uh, uh, sarcomas.

48:55

So that would be the reasoning why I would think, you know,

48:57

I would lead with the sarcoma here. Certainly mets, if known, you know,

49:00

malignancy, uh, would be there. And then, uh,

49:03

nerve sheet tumor would be less likely. Consideration also on board, on,

49:06

on when, when it, when I see a case like this. So further discussion,

49:11

this end up being a synovial sarcoma. Now,

49:13

head and neck sarcomas are in general rare,

49:16

and they represent 0.1% of the head and neck tumors, uh,

49:20

overall, and they're only three to 10% of the, uh, you know,

49:25

sarcomas in general. Uh, and, and then, uh,

49:29

sarcomas overall are in general where,

49:31

and they constitute 1% of all of the solid malignancies. Now,

49:34

synovial sarcomas do overlap with other sarcomas,

49:36

but they are a little bit less aggressive historically. And then classically,

49:40

they are located predominantly in the extremities.

49:43

The worst synovial is a misnomer, right?

49:45

'cause it's not associated with the synovium of a joint.

49:48

And they're most likely or most commonly affect, you know,

49:51

males in their third to fifth decade within the lower extremities. But again,

49:55

as I said, you know, they can occur in the head and neck, exceedingly rare,

49:58

1.1%. If they are in the head and neck, they typically, you know,

50:03

most common location is the peral space and the hypopharynx followed by the

50:07

masticator space, and they tend to be well circumscribed,

50:11

T two hyperintensity alene enhancing as this case. Now,

50:14

when do I consider sarcomas,

50:16

when I'm looking at head and neck lesions versus carcinoma? Now,

50:19

the predominant malignancies obviously are gonna be carcinomas,

50:23

but location help with the, the, the diagnosis. So in general,

50:27

carcinomas are either gonna be cutaneous, right, or they're gonna be relate.

50:31

And those should be relatively straightforward to diagnose, uh,

50:35

and differentiate with sarcomas, with the exception of angios sarcomas.

50:39

Now in the, uh, and or they're gonna be along the mucosal surface.

50:42

So they tend to be deeper or more, uh,

50:45

central versus the sarcomas in general. The other thing is, uh,

50:50

risk factors. So obviously, you know, with carcinomas,

50:53

we know H P V association or, you know, potentially smoking, which, you know,

50:57

most of the time is, is not typically for most of the sarcomas and age.

51:00

A lot of the sarcomas are in younger adults, you know, not,

51:04

not taking into account H P V, obviously, and then lymph nodes. So one,

51:08

another big thing is if it's a lymphoma or carcinoma,

51:11

they're more likely to go to lymph nodes versus sarcomas.

51:14

Sarcomas can go obviously to lymph node,

51:15

but more likely there will demonstrate a hematogenous spread. So, you know,

51:20

to follow up with that, a question, and, and,

51:22

and you can think of is that another masticator space lesion,

51:25

and I'm looking at this as situated within, you know,

51:27

predominantly the medial TER muscle, you know, uh,

51:30

very homogeneously enhancing T two, hyperintense, well circumscribed,

51:33

and then this, this is sarcoma or carcinoma.

51:36

If I'm looking at it and having to choose between the two. And then I, you know,

51:39

I would definitely lean to sarcoma given the overall appearance and location.

51:43

And this ended up being spindle cell, uh, sarcoma.

51:46

So following up and talking about those spaces and potential spaces, the,

51:50

you know, the masticator space, one of the most common, uh,

51:54

the most common pathologies is infection, spread of infection,

51:57

in particular dental infection. Uh,

52:00

this is a patient that had a cyto nasal malignancy. As you can see,

52:03

there's extensive cyto nasal surgery. And then they, uh, post-radiation,

52:07

they had an ulceration along the mucosa, and then, uh,

52:11

they had a superimposed infection. And if you look closely, you will see that,

52:14

uh, sub mesic meric space. And then even the OID space of the ma uh,

52:20

masticator space, you will see, uh, areas of subperiosteal abscess formation.

52:24

So again, you know, uh, infection is one of the most common in,

52:27

in particular orogenic pathologies of the masticator space and something that we

52:31

see very frequently. Another, uh, another lesion that we typically tend to see,

52:35

and it's a little bit more straightforward, is obviously osteosarcomas, uh,

52:39

such as this one here is arising from the ramus. Uh, and, uh, the,

52:43

this patient previously had a lesion that was resected and you can see a large

52:47

recurrence. And then the osteosarcomas tend to have that, you know,

52:51

peri osteo bone reaction. Occasionally the sunburst not here.

52:54

And then comans triad with the lift of the, uh, uh, the periosteum, again,

52:58

not here in this case. And then they, to a varying degree,

53:01

have a soft tissue component, uh, such as this case here. This was, you know,

53:04

a ma mandibular ator space, uh, osteosarcoma that had occurred and,

53:09

and gone into adjacent, uh, space. So to recap, domesticated space,

53:14

it is a space that is very challenging to see on physical exam.

53:18

So imaging plays a central role in diagnosis.

53:21

So we as radiologists should make ourself familiar with it.

53:25

And then it's really important to differentiate between, uh,

53:27

lesions occurring primarily in the masticator space when it comes to

53:31

differential and lesions is spreading to masticator space.

53:34

'cause recurrent and primary carcinomas can frequently extend, uh,

53:38

remember infection and inflammation is exceedingly common,

53:40

especially odontogenic vascular malformation is a more common, uh,

53:44

presentation in pediatrics.

53:46

And we went across one of those lesions in a different space.

53:49

And then neurogenic arising from the actual, you know, V three segments.

53:53

And then remember as Dr. Uh,

53:55

Guzman showed us some examples of perineural spread masticator space do have V

53:59

three branches, and, you know, uh, spread from, uh,

54:02

primary head and neck malignancies is not uncommon. And lastly, you know,

54:06

demandable is part of the space. So pathologies of osseous,

54:09

lesions of demandable are things to think of when you see a masticator space

54:13

lesion. With that, you know, going back to the question,

54:17

which of the following is not a masticator space muscle?

54:24

Yep, absolutely. You know,

54:26

and then we just talked about the temporalis muscle and, you know,

54:29

being part of the supra zygomatic masticator space and then the medial Reid

54:34

muscle, we, we discussed, uh, as, you know,

54:36

part of the masticator of the infra temporalis. And again, you know,

54:39

making yourself familiar with all of these terminologies that vary from a person

54:43

to person and and the literature in between surgeons and radiologists. Okay.

54:47

And with that, I think this is our last case. Uh,

54:50

I'm happy to stick around and answer any questions if anyone has any questions.

54:55

Thank you so much, Dr. Guzman and Dr. Alday. Yes, at this time,

54:58

we'll open the floor for any questions from our audience.

55:01

You can submit your questions through that q and a feature in Zoom,

55:06

so we can get to as many as we can before we have to close.

55:11

Well, I would mention that, um, if any of you have any questions and uh,

55:16

you would like to email either myself or Dr. Alday, please feel free to do so.

55:21

We'd be certainly happy to answer any questions for you. Uh, offline,

55:27

We have one that may have just come through.

55:30

Are there any good articles to refer for neural spread of tumors?

55:35

Um, there actually are, but um, it, uh,

55:39

there's better than that is a, um, a book by Dr.

55:44

Hornberger, um, uh, that,

55:48

that is a head and neck, uh, tumor. Um, uh,

55:52

let me see if I can find, it's a, um, title here

55:57

where it's a case based type of book. It's called, um,

56:02

diagnostic Imaging and Head and Neck. Um, and again, it is, um,

56:06

a book that is, um, edited by Dr. Harberger.

56:11

It's one of the, um, amus, um, volumes,

56:15

and they have excellent, um, case-based, um, anatomy,

56:19

explanation of all the abnormalities of the head and neck,

56:23

including the supra hyoid space, as well as, uh, excellent, um,

56:27

differential diagnosis with, um,

56:29

images of every differential diagnosis as well. Um, so, uh,

56:34

it is a little bit pricey. It's almost $250, but if you can get it, that would,

56:38

it's a great resource.

56:40

What is the most common metastatic to you for the masticator space?

56:45

Rammi, do you wanna take that one?

56:47

Absolutely. So I, I will add to Dr. Guzman that, that the doc,

56:50

the Bookshare is fantastic. The other book I'll say is, is Dr.

56:54

Somms Peter Somms Encyclopedia, but that's, they have,

56:57

he has a very large chapter on peroneal spread about 60 or 70, uh, pages,

57:01

which is fantastic. But the problem is obviously, I mean, affording it if it's,

57:05

it's not a cheap book, but it's a fantastic, uh, chapter.

57:10

And then the other thing, there's a few articles by Dr. Uh, Lawrence Ginsburg,

57:14

uh, discussing, you know, more rare perineural spread in different, uh, uh,

57:18

areas in different branches in the head and neck, which is,

57:20

which are also very fantastic now regarding the, uh, uh, ator space.

57:24

So look at it into two different components. If I'm looking at osseous,

57:28

and it's not metastatic,

57:29

but something that is very common and I see on a weekly basis is multiple

57:33

myeloma and prostate going to the mandible. And in matter of fact, you know,

57:36

not uncommonly, we see people coming in with numbness of the face that have,

57:41

you know, multiple myeloma and they have, you know,

57:43

significant tumor burden involving that inferior alveolar nerve and, and,

57:47

you know, the mandibular canal. Uh, so prost, I'd say,

57:50

if you're looking at the mandibular itself,

57:52

if you're looking at the muscle itself, it's very variable.

57:55

But one of the things that I see more common, and don't quote me on this,

57:58

this is my experience, but not the literature, I don't know of the literature,

58:01

is renal cell carcinoma. I've seen decent number of cases,

58:05

but I don't know exactly, you know, if someone looked at it in the literature,

58:09

I'm not aware of that data. Dr. Dr. Guzman, are you aware of any of that data

58:13

For metastatic disease to domestic cancer? Me,

58:16

Outside of Ossis and, you know,

58:20

No, no, I, I wouldn't know.

58:22

Yeah, I would say definitely Ossis would be number one. And you, you know,

58:25

prostate and, and, and then myeloma not being, you know, not being metastatic,

58:29

but more, you know, intrinsic and then renal from my experience. But definitely,

58:33

you know, a lot of other things.

58:36

Good. And then for the next question, so, you know, again,

58:41

70% of carotid tumors are benign, plu, amorphic, adenoma.

58:47

Um, so when you do see, um, um, orlu, uh,

58:51

or perineal spread of disease,

58:52

then you have to be concerned about more aggressive tumors.

58:57

And cystic carcinoma has to be included in differe differentials or other

59:01

things. Again,

59:01

that can give you peroneal spread of disease or SMM cell carcinoma. Um,

59:06

certainly melanoma, other metastatic diseases less commonly.

59:10

So I would turn the question around and say that when you do see urals spur

59:15

disease, you must always include adeno cystic carcinoma differential,

59:19

although of course, you know, it could be other things as well.

59:23

And I would agree with Dr. Guzman. I will only also add,

59:26

remember that these lesions can skip and the perinatal spread, right?

59:30

So you guys want to, uh, follow the whole course of the nerve before you, uh,

59:36

you make the, uh, you know, assess all of the nerve before, you know, just,

59:39

you know, closing the case and saying, okay,

59:41

there's peroneal spread here or there. Just, you know,

59:43

make sure you follow all of the nerve. Of course,

59:45

especially with endo cystic carcinoma, they tend to, to uh, spread.

59:50

Okay. And then regarding the, uh, boundaries of the, uh, retro mota, I think Dr.

59:54

Guzman had to, to catch your patient. So, uh, you know, the, the boundaries,

59:59

essentially, if you look anteriorly, it'll be, uh, the,

60:04

uh, you know, uh, buccal space posteriorly,

60:07

you are talking about peripheral gene in masticator space. Uh,

60:12

and then one thing I will say, understanding re molar, uh,

60:15

trig is outside of it being a hidden space,

60:18

once you ex reach that area, the, uh,

60:22

spread of tumor just becomes endless. So it, and it's very hidden. Also,

60:26

it's very challenge for us on cts because of the dental amalgam, right?

60:29

So make sure, you know, you get angled views if you,

60:32

if you read a large volume of tumors.

60:34

'cause sometimes you will miss tumors with, uh,

60:37

based on just regular axial through the, uh, the, the, the neck area.

60:42

And then how do carcinoma and sarcoma differ with respect to enhancement and

60:45

bone destruction in general? You know,

60:49

these sarcomas are a whole gamut of, of different, uh, aggressiveness.

60:53

So some of them will, will enhance very significantly. Some of them will not,

60:57

but most of them do tend to enhance pretty strongly. Uh,

61:01

and then they tend to, uh, uh,

61:04

destroy or remodel bone depending on how aggressive they are. So like some,

61:08

something like synovial sarcoma,

61:10

like this sarcoma tend to first push or remodeling before it destroys.

61:14

Similar with, with, you know, spindle cell, but there are, you know,

61:17

sarcomas that are a little bit more aggressive. Um, and then, uh,

61:21

when it comes to, uh, carcinomas, now we do know a lot of, you know, mucosal,

61:25

gingival mucosal and buccal mucosal tend to vary early on, you know, uh,

61:29

invade that mandible, whether, you know, minimal or significant destruction. So,

61:34

you know, in advanced disease or T four disease, when we stage these, uh,

61:38

a lot of times you'll see very frequently oste destruction with carcinomas and

61:42

then the enhancement. You know,

61:44

I would say that it is really hard to just use an enhancement on its own to

61:48

differentiate between the two entities. Again, just because the, the fact that,

61:53

uh, sarcomas are of, of different flavor and different aggressiveness.

61:58

Awesome. Thank you so much for staying on to answer those extra questions Dr.

62:02

Alday. And, uh, thank you so much for the case review today. This was awesome.

62:07

And for our awesome audience for participating in all the questions

62:12

and asking all the questions,

62:15

you can access a recording of today's conference and all our previous noom

62:18

conferences by creating a free M r I online account.

62:21

And be sure to join us next week. We've got two noom conferences.

62:24

We've got one on Tuesday, October 17th, and we're featuring Dr.

62:28

Inez Mohamed for a lecture entitled Psychological Safety as an A C G

62:33

ME Requirement Challenges and Solutions. And then on Thursday,

62:37

October 19th, Dr.

62:39

Steven Rowe is going to join us for a lecture called Current Radiopharmaceutical

62:43

Theranostic Applications in Nuclear Medicine.

62:45

You can register for those lectures@mmrionline.com.

62:48

Follow us on social media for updates on future NOOM conferences. Thank you, Dr.

62:53

Guzman. Thank you Dr. Aya and everyone. Have a great day.