0:01

Let's look at a couple more examples on slides of

0:05

typical appearances of the pleomorphic adenoma.

0:08

Here we have T1 weighted,

0:10

T2 weighted, and post-gad fat-sat

0:13

T1 weighted sequences.

0:15

These are not VIBE or CISS imaging.

0:18

These are traditional pulse sequences,

0:20

traditional axial T1 rather than VIBE,

0:23

traditional STIR T2 rather than CISS,

0:26

and traditional post-gad T1 rather than

0:29

post-gad VIBE. On these sequences,

0:32

you can see that the typical pleomorphic adenoma is

0:35

intermediate in signal intensity on T1 weighted imaging.

0:40

Basically, dark in signal.

0:42

In this case,

0:42

it is in that superficial portion of the parotid

0:45

tissue that overrides the masseter muscle.

0:49

On the T2 weighted scan,

0:50

this is purely bright in signal intensity.

0:53

In fact,

0:54

in some cases, it's so bright that you might say,

0:57

is that a cyst?

0:58

Is that a cyst that may have, you know,

1:00

some hemorrhage or some tissue?

1:03

I mean, the dark signal on the T1 is almost that of CSF.

1:09

On T2, it's the same as CSF.

1:11

Look how bright it is on that STIR image.

1:14

And you scratch your head and say,

1:16

am I dealing with a parotid gland cyst?

1:18

This is the value of the post-gadolinium enhanced scans.

1:22

So on the post-gadolinium fat-sat scan,

1:24

we see that this lesion enhances avidly.

1:28

It's very bright on the post-gad compared

1:30

to the pre-gad T1 weighted sequence.

1:33

So this is our stereotypical pleomorphic adenoma.

1:37

I wish I could say that all of them look like this.

1:41

We'll just say we'll use the 80% rule.

1:43

80% of the pleomorphic adenomas have this classic

1:46

appearance of being bright on T2 lobulated

1:51

margins and enhancing avidly.

1:54

You will...

1:55

You should look for a hypointense rim around the

1:59

border of the pleomorphic adenoma

2:03

representing the capsule.

2:05

And this was an ABR, maintenance of certification

2:08

question that was asked

2:11

as being typical of the pleomorphic adenoma.

2:14

Just to refresh your memory with the anatomy,

2:16

here's our superficial portion of the parotid gland.

2:19

Here we can see Stensen's duct inserting

2:22

at the second molar buccal mucosa.

2:27

Here's our zygomaticus muscle,

2:29

similar anatomy on the contralateral side.

2:32

Let's show another example.

2:37

Here is a patient who has a

2:41

right-sided parotid mass.

2:44

And in this situation, we again

2:47

see well-defined borders.

2:53

We see a dark rim at the border of the tumor with

2:58

the native parotid gland.

3:01

In this case, it doesn't light up quite as nicely.

3:04

And this may be because this is more of a cyst

3:08

sequence rather than a STIR sequence.

3:12

And on post-gadolinium enhanced scanning,

3:14

it enhances avidly,

3:19

pleomorphic adenoma of the right parotid gland.

3:24

It these are two different patients who have

3:29

pleomorphic adenomas of the soft palate.

3:34

Unfortunately, the cases above have been biopsied,

3:38

and what you're seeing centrally within

3:40

the mass is some hemorrhage,

3:44

that being this brighter tissue here,

3:47

but the whole uvula soft palate

3:52

mass is the pleomorphic adenoma.

3:55

Compare that with this individual.

3:58

We are looking again at the soft palate.

4:01

This is the

4:03

palatine tonsil junction with the nasopharynx,

4:08

and you see a well-defined mass

4:12

which has bright signal intensity

4:15

on T2-weighted imaging on the fat-sat.

4:19

It has that hypointense rim

4:24

that the ABR identified as one of the characteristic

4:29

features of pleomorphic adenomas

4:32

that is an encapsulated mass.

4:34

It might be lobulated,

4:35

but by and large, it's an encapsulated mass.