0:00

The evaluation of malignancies of the sinonasal

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cavity is somewhat difficult because most entities

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have the same signal intensity characteristics

0:10

on T1 and T2-weighted MRI scan.

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In this case, what we see on the pre-GAD T1

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weighted scan is a very large mass emanating

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from the maxillary sinus, growing through the

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anterior wall of the maxillary sinus into the

0:25

soft tissues of the subcutaneous skin, and

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the face. And this lesion also

0:33

grows into the orbit.

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You can see this growth into the extraconal

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space and along the lacrimal sac of the left

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orbit. The globe is displaced laterally.

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On the T2-weighted scan, you see that this

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lesion has very dark signal intensity,

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which is characteristic of most

0:52

malignancies of the sinonasal cavity.

0:55

However, as I mentioned previously, this

0:57

is also a feature of inverted papilloma.

1:00

Can we say that this is not

1:02

a cerebriform appearance?

1:04

It really doesn't have that gyral pattern or the

1:07

bright signal intensity of "sulci"

1:11

that you would see with an inverted papilloma,

1:13

but I wouldn't base my diagnosis on that.

1:17

In this case, on the post-gadolinium

1:19

enhanced scan, you also see the involvement

1:21

here where it's displacing the

1:24

medial rectus muscle and abutting on

1:27

the inferomedial portion of the globe.

1:31

It's growing into the soft tissues

1:33

of the subcutaneous tissue.

1:35

We want to make sure that it's not

1:36

growing into the cavernous sinus region.

1:39

And the other area of concern, obviously, would be

1:42

in the pterygopalatine fossa. So the pterygopalatine

1:45

fossa seen here usually has

1:48

bright signal intensity fat within it.

1:51

Here on the contralateral left side, the soft

1:54

tissue is growing into the pterygopalatine fossa.

1:57

What's the importance of that?

1:59

Once it's into the pterygopalatine fossa,

2:02

you have the way station of the second

2:05

division of the fifth cranial nerve —

2:06

the maxillary nerve.

2:08

When I see that there's involvement of the

2:10

pterygopalatine fossa, I have to worry about

2:12

potential spread along that fifth cranial nerve.

2:15

So you wanna be cognizant of looking along the

2:18

foramen rotundum, which is seen here but is

2:21

normal, along the Vidian canal, which is seen here,

2:24

but is normal, along the inferior orbital fissure.

2:27

Which, unfortunately in this patient,

2:29

there is invasion of the inferior orbital

2:31

fissure leading into the orbit, seen here.

2:35

Down low, you have the greater and lesser palatine

2:38

foramina, which can lead into the hard palate.

2:41

And then you want to look at the potential spread

2:44

laterally into the pterygomaxillary fissure,

2:48

where it may lead into the masticator space.

2:51

Here we have soft tissue, which is outside

2:54

the maxillary antrum, and growing into the

2:57

masticator space from lateral spread

3:00

through the pterygomaxillary fissure.

3:03

So this is a very aggressive squamous

3:06

cell carcinoma, the most common

3:09

histology to affect the maxillary antrum.