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Hello everyone, my name is

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Dr. Sidney Levy, and today I'm here to discuss the diagnosis

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and staging of oral tongue squamous cell malignancy.

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In previous vignettes, we've been discussing the

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anatomy of the oral cavity and its subsites.

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Now I'd like to move along to describing the

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characteristics of squamous cell malignancy in this region.

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I have identified a case of left lateral oral

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tongue squamous cell malignancy, which I'd like to use to

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demonstrate the general principles of its MR appearance.

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And then in our next vignette,

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we will go on to stage the tumor.

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So firstly, I have axial sequences:

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pre-contrast T1 without fat suppression,

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post-contrast T1 with fat suppression,

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coronal T2 weighted imaging with fat

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suppression, and sagittal post-contrast

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T1 weighted imaging with fat suppression.

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The malignancy is identified here.

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It is involving the lateral margin of the tongue.

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That is the most common site of oral tongue squamous cell

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malignancy, followed by the undersurface and the dorsum

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and the tip.

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The undersurface of the oral tongue is

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generally considered with the floor of the mouth.

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So if that is the site of origin of the

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tumor, it is generally considered a floor of

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mouth tumor rather than an oral tongue tumor.

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This MRI demonstrates a T1 hypointense

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tumor with respect to normal tongue mucosa.

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I'm now going to draw its margins for you so that

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you can appreciate what I'm trying to describe.

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The tumor itself is here; you can see

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it more easily on the post-contrast T1.

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The T2-weighted imaging, it is extending

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inferiorly into the floor of the mouth, here.

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And on the sagittal imaging, it is

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involving the undersurface of the oral

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tongue and the adjacent floor of the mouth.

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So therefore, it is an oral tongue malignancy

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that has extended directly into the

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ipsilateral left floor of the mouth.

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So what do we describe when we have these lesions?

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Firstly, you need to give a dimension because

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staging is determined by the dimensions of the tumor.

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You need to look for the maximal dimension.

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In this case, it's about 5 centimeters

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in the sagittal projection.

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You also need to document whether

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there is crossing of the midline.

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In this case, it's a challenge.

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And the reason for that is that we have one

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image here, where there is indeed bulging of the

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tumor at the level of the midline, just here.

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Now you can't see it clearly cross over to

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the right side, but there's certainly bulging.

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And there would certainly be suspicion that the tumor is

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about to or has begun to extend to the contralateral side.

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Why is that important?

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Because that helps determine the

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degree of surgical resection.

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How much tongue needs to be removed at the time of surgery?

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You also need to document the depth of invasion.

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So the depth of invasion is a new criterion

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in the staging of oral cavity malignancy,

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which was introduced in the eighth edition of

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the AJCC guidelines at the beginning of 2018.

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So at its thickest portion, this tumor is clearly

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well more than 10 millimeters in depth of invasion.

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So it's a high-stage tumor purely based on that.

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We've documented that it extends to the floor of the mouth.

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It does not extend to any other oral cavity subsites.

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So the last thing we need to consider

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is what are the differentials?

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Could this be a base of tongue squamous cell carcinoma?

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No, it can't be.

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The posterior third of the tongue is spared.

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79 00:04:13,155 --> 00:04:15,035 This is an oral tongue malignancy

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restricted to the anterior two-thirds.

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Could it be a floor of mouth malignancy

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spreading to the oral tongue?

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Its center is really within the oral tongue and although

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it does extend inferiorly into the floor of the mouth, it would

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be classified as an oral tongue tumor by most radiologists.

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Does it look like any other lesions that, uh,

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occur in this region, such as schwannomas?

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Doesn't look like a schwannoma.

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Schwannomas are well circumscribed

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in general and enhance strongly.

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Often associated with the lingual nerve in this region.

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Could it be a venous malformation?

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It is a mass.

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It's not really a collection of tortuous vessels.

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So, not really thinking of that.

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Abscesses can occur in the oral tongue.

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However, they have typical features of abscesses

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such as a necrotic center and a peripheral rim.

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So really we have a standard case of an oral tongue squamous

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cell malignancy, and we will move on to lymph nodes.

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So for lymph nodes, it's important to refresh

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your memory on the lymph node levels.

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We have three abnormal lymph nodes in this patient.

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They are in level IIa bilaterally,

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so both these lymph nodes here.

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And then, on the left-hand side, we have another

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lymph node which is heading into level III, below

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the level of the inferior border of the hyoid.

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And lastly, you need to look for any evidence of

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distant malignancy, which there isn't in this patient.

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So in our next vignette, we will formally stage this patient

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according to the AJCC 8th edition guidelines, TNM staging.