0:01

So here's an example of a diffuse

0:03

abnormality involving the oral tongue and

0:05

then extending into the floor of the mouth.

0:07

So when we look at the non-contrast T1

0:10

weighted images, we can see this intermediate

0:12

signal mass that's involving the oral tongue on

0:15

the sagittal images, the T2 weighted images.

0:18

This defines the extent of this abnormality.

0:21

When you give contrast, you can see that there

0:23

is patchy enhancement to this diffuse abnormality,

0:26

indicating that there is a vascular supply.

0:30

Now, could this be a very

0:31

aggressive squamous cell carcinoma?

0:33

I assume it's possible, but in general, squamous cell

0:36

carcinomas don't present at this extensive stage.

0:40

So this was a younger patient, and

0:42

the patient had a known congenital

0:43

malformation involved in the oral tongue

0:45

in the oral cavity.

0:47

So now we have a congenital malformation,

0:49

and the issue is how do we classify this?

0:53

Well, the way that I classify it,

0:55

again, to get us through 80% of these,

0:57

is that we divide these into four areas.

1:00

There is arterial, there is venous, there

1:03

is capillary, and then there is lymphatic.

1:07

So if we understand the four rings,

1:09

if you will, the Olympic rings,

1:11

and we look at various components of

1:14

these within various malformations,

1:16

this will again, will get us through

1:17

about 80% of the common vascular lesions

1:20

that we'll be seeing in our practice.

1:22

So how do we dissect this case?

1:25

Well, the first thing that we do is we

1:26

look at the T2 weighted sequences,

1:28

which is located at the top left.

1:30

And when we look at the T2 weighted sequences, we

1:32

can see that there's areas of increased T2 signal.

1:36

So when we see these areas of

1:38

increased T2 signal, that tells us

1:41

that there is a lymphatic

1:42

component to this malformation.

1:45

The next thing that we look at is we can see

1:47

this abnormality is involving muscle, and not

1:50

only is it involving muscle, when we look at

1:52

the coronal T2 weighted images, we can see

1:55

these focal areas of diminished signal, and

1:58

these focal areas of diminished signal are phleboliths.

2:02

So in venous malformations, the characteristic

2:05

findings for venous malformations

2:06

are muscle involvement and phleboliths.

2:09

So now we know that we have a venous malformation.

2:12

Now, in one of the other earlier cases we

2:15

showed, we saw components of a lymphatic

2:18

component and a venous component, and that was

2:20

referred to as a veno-lymphatic malformation.

2:24

That case did not have any appreciable enhancement.

2:27

But when we look at the contrast-enhanced

2:29

T1 weighted images, we can see that

2:32

there's quite a bit of enhancement.

2:34

And in fact, when we look at this, a lot of this

2:36

is some, a little bit of fine linear enhancement,

2:39

suggesting that there's a capillary component.

2:41

So now we have a capillary component.

2:45

The fourth component is arterial.

2:47

And in order to have an arterial component, then

2:49

that is the classic arteriovenous malformation.

2:53

In general, if you have an arteriovenous

2:55

malformation, you don't have enlargement of the

2:57

soft tissues, but instead you tend to have atrophy.

3:01

Why?

3:02

Because normally an artery goes to

3:04

a capillary, it goes to the vein.

3:06

The capillaries allow nutrient exchange

3:09

with the surrounding soft tissues.

3:11

If you have a direct communication

3:13

between an artery and a vein, you don't

3:14

have the capillaries, and as a result,

3:17

there's no way for the nutrients to diffuse out into

3:20

the soft tissues and nourish those soft tissues.

3:23

And if there's not enough nutrients, then all of

3:25

a sudden the soft tissues retract—the atrophy.

3:29

So instead of having a lot of soft

3:31

tissues, you have smaller soft tissues.

3:33

So that's why this does not have

3:35

an arterial component to it.

3:37

In general, when we classify vascular malformations,

3:42

if there's two components—a lymphatic and

3:44

venous—this is a veno-lymphatic malformation.

3:47

If it's capillary and venous, it's

3:49

a capillary-venous malformation.

3:51

If it's lymphatic and capillaries,

3:53

it's a capillary-lymphatic malformation.

3:55

But if there are greater than

3:57

two components, as is seen here,

4:00

this is what we refer to as a mixed vascular

4:03

malformation. So this construct will get you

4:06

through the majority of congenital vascular

4:09

malformations that you'll encounter

4:12

involving the extracranial head and neck.

4:15

In order to confirm this diagnosis, we performed

4:18

a time-resolved MR angiography, and what the

4:21

time-resolved MR angiography demonstrates is

4:24

that there is diffuse enhancement involving

4:27

this large vascular malformation

4:30

involving the oral tongue, but notice

4:32

how there's not large vessels feeding it.

4:34

Rather, this is more of a diffuse capillary

4:37

blush as opposed to large vessels.

4:40

So that's why the differential diagnosis here would

4:44

include a component of a capillary malformation, a

4:47

lymphatic malformation, and a venous malformation.

4:51

And because there are more than two components, we

4:53

would classify this as a mixed vascular malformation.