0:01

So this is an example of adenoid cystic

0:03

carcinoma involving the floor of the mouth.

0:05

So the imaging findings, first of all, for

0:07

adenoid cystic, are completely non-specific,

0:10

and the case that I'm about to show you now

0:12

could easily be squamous cell carcinoma.

0:14

But I'll give you one little tip

0:16

that you can potentially suggest

0:18

that this is adenoid cystic carcinoma.

0:20

And again, it's all based on the anatomy.

0:22

So when we look at the floor of the mouth,

0:24

we can see this mass right here that's involving

0:26

the anterolateral aspect of the floor of the mouth.

0:29

It is intermediate signal on T1, and we

0:31

can see that there's lateral displacement

0:34

of the geniohyoid-genioglossus complex.

0:37

When we give contrast, we can see

0:38

that this mass is avidly enhancing.

0:41

Again, this can be seen

0:42

with squamous cell carcinoma or any

0:44

type of minor salivary gland tumor.

0:47

When we look at the T2-weighted images,

0:48

we can see that it's heterogeneous, and there

0:50

is a focal area of high signal within it.

0:54

Sometimes that can be suggestive of a minor

0:56

salivary gland tumor, such as adenoid cystic,

0:58

mucoepidermoid, but again, it's not really specific.

1:02

Part of the way to at least suggest

1:04

the diagnosis is the following.

1:06

If we draw a line down the middle involving the

1:09

anterior floor of the mouth, and we look at the patient's

1:11

left side, we can see the mylohyoid muscle here.

1:14

We can then see the fat just medial to it.

1:17

Then we can see the hyoglossus muscle,

1:20

and then we have another stripe of fat, and then

1:22

we have the genioglossus-geniohyoid complex.

1:25

One way to suggest the possibility of a minor

1:27

salivary gland carcinoma is that we know that

1:31

the sublingual gland is located between the

1:33

mylohyoid muscle and the hyoglossus muscle.

1:36

So when we look really closely, we can see

1:38

the mylohyoid being displaced laterally,

1:41

and the hyoglossus muscle being displaced medially.

1:44

This displaces this lesion in the floor of the mouth,

1:47

and in the expected location of the sublingual gland.

1:51

So theoretically, if we do see a mass, and

1:53

you can see this on the coronal images, that is

1:55

laterally displaced the mylohyoid muscle,

1:58

and then medially displaced the hyoglossus muscle,

2:01

this places this in the sublingual gland.

2:04

So this would increase the likelihood

2:07

that we are looking for a tumor that's

2:10

arising from salivary gland origin.

2:12

So therefore, in addition to squamous cell carcinoma,

2:15

we would think of a salivary gland neoplasm, such as

2:19

adenoid cystic or mucoepidermoid carcinoma.

2:22

And in this particular case, this

2:23

was adenoid cystic carcinoma.