0:01

So here's a patient that presents with

0:02

a mass involving their oral tongue.

0:05

And when we look at the non-contrast T1-

0:07

weighted image, we really don't see much.

0:09

Now, maybe with the subtle leap of faith, you

0:12

can suggest that some of the fat here involving

0:15

the left half of the oral tongue is obliterated

0:17

on the right, but it's sort of a tough call.

0:20

But anyway, so it's essentially

0:21

intermediate signal on T1.

0:23

On T2-weighted images,

0:24

we can see that it's very, very bright.

0:26

And when we give contrast,

0:28

there's no enhancement whatsoever.

0:29

So this tells us that we're dealing with

0:32

a cystic mass involving the oral cavity,

0:36

specifically involving the oral tongue.

0:39

When we look at the diffusion-weighted sequences, we

0:43

can see that it's high signal on the DWI sequences.

0:47

And when we look at the ADC map, we

0:49

can see that there is increased signal

0:51

on ADC, probably due to shine-through.

0:54

So what I'm showing here right now is a cystic

0:57

lesion involving the floor of the mouth.

0:59

The patient does not have any history of

1:01

fever, and it's been there for a long time.

1:04

So this is a congenital lesion.

1:06

It's a congenital vascular lesion,

1:09

and this is a lymphatic malformation.

1:12

Now the other differential diagnosis that has

1:14

to be considered when you see something like

1:16

this on the T2 sequences, the non-contrast

1:20

T1 and the contrast-enhanced T1

1:22

sequences is the possibility of an epidermoid.

1:26

So how do we differentiate between a

1:28

lymphatic malformation and an epidermoid?

1:32

Where we look at the diffusion sequences.

1:34

So this is high signal on DWI, but the fact that

1:37

the ADC value is high signal, that suggests

1:41

a lymphatic malformation.

1:43

If the ADC value was decreased, then this would

1:46

suggest that we're dealing with an epidermoid.

1:49

And when we look at the dynamic sequences, we

1:52

can see that there's no enhancement whatsoever.

1:55

And this confirms that this cystic lesion

1:58

does not have an appreciable vascular supply.

2:01

So before, when I talked about the four

2:03

main components, which were arterial,

2:05

venous, lymphatic, and capillary,

2:08

we can see there's no enhancement.

2:10

So this really is a lymphatic

2:12

malformation involving the oral tongue.