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Hello, everyone.

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Sidney Levy here continuing our discussion on the

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diagnosis and staging of oral cavity malignancy.

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In particular, hard palate malignancy in this vignette.

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So, I'd like to begin with the

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T staging of these tumors.

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And as with all oral cavity squamous cell

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malignancies, the first thing to do is to

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get a maximal dimension on the tumor.

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So, in this case, we have a sagittal and

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a coronal projection, and the tumor is

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coming out at approximately 3 centimeters.

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The next thing we look for is depth of invasion.

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This tumor is clearly invading

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into the sinonasal cavity.

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Uh, it will be well more than 10 millimeters of

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depth of invasion, which is the threshold.

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So, we have no issues there.

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This tumor is clearly above the threshold

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for increased depth of invasion.

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Next point to look for, has there been invasion

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of the cortical bone of the maxilla or maxillary sinus in

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order to upgrade it to moderately advanced disease?

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In this case, this tumor has directly

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invaded into the sinonasal cavity.

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So, let me draw that for you.

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We have the hard palate here, and then we have

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this tumor extending superiorly into

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the left nasal cavity.

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And while it's bulging against the

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maxillary sinus, there isn't any conclusive

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evidence that it's actually broken through.

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So, at the moment, this tumor is already a T4A tumor

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because it has invaded cortical bone of maxilla.

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The last thing to consider is, has it

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extended far enough back that it's threatening

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the pterygoid plates or the skull base?

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Or is it encasing the internal carotid artery?

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Or has it reached the masticator space?

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So, to do that, we need to go to the axial images.

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Hard palate is difficult to identify on axial imaging.

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And often, axial imaging is the first

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set of sequences that you will look at.

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So, this outlines the point that it's

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important to actually start with the coronals

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and the sagittals with the hard palate.

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This is the tumor here.

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If you looked at this and you didn't know

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any better, you would call it a nasal,

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you would call it a sinonasal tumor.

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Uh, and it's easy to confuse the two.

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But fortunately, we can see the

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pterygoid plates well on this study.

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So, let me point them out to you.

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Here, here, here, and here.

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And they are not involved by tumor.

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The skull base is not involved.

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The masticator space is not involved.

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Let me point that out to you as well.

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They are spared, and it's a long way from

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the internal carotid arteries, so we don't

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need to worry about them in this study.

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They are all the way back here, carotid space.

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This tumor does not have any abnormal lymphadenopathy

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within the head and neck, and there was no evidence

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of distant disease on the MRI that was performed.

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So, in summary, this tumor is a T4A N0 M0 tumor.

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And the reason for that is that it is invading cortical

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bone of the maxilla into the sinonasal cavity without

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extension to the pterygoid plates or skull base.

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The last thing to mention, although it's not formally

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part of the staging, is that this tumor did not

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demonstrate any evidence of perineural infiltration.

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But if that was present, you would mention it.

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It's also worth mentioning that the

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tumor does not cross the midline

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because the surgeon always wants to know

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that if they're contemplating a resection.

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In this case, it is bulging against the midline, but

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you would not say that it's clearly crossed over.

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Thank you.