0:01

This patient is a 40-year-old female.

0:03

History is to evaluate a liver lesion.

0:06

We got an MRI of the abdomen with or without

0:09

intravenous contrast to evaluate the finding.

0:12

We're going to focus on the gallbladder, and so we'll

0:14

start off with the axial T2 non-fat-saturated image.

0:19

And I've just sort of zoomed up a

0:21

little bit on the gallbladder itself.

0:22

Let me just scroll through it nicely one time.

0:27

As you see it, you can see that there are multiple

0:29

little filling defects inside of the gallbladder.

0:33

You notice that they're all sort of associated with

0:35

the wall of the gallbladder protruding inwards,

0:38

and there are numerous, many of them, right?

0:40

There's got to be at least 10.

0:43

I mean, there's probably many more than that.

0:46

And so that's sort of a different

0:48

appearance of what we've seen so far.

0:50

Gallstones can lie dependently; a lot

0:52

of the time they float, but a lot of

0:54

these are really round in appearance.

0:57

They're all about the same size, and almost all of

0:59

them are associated with the wall of the gallbladder.

1:02

What do they look like on the

1:04

axial T2 fat-saturated image?

1:07

Well, they look pretty similar.

1:08

T2 hypointense, associated for the most

1:10

part with the wall of the gallbladder, and

1:12

numerous findings as we can see over here.

1:15

We'll look at the T1 fat-sat pre-contrast image to

1:19

see if this has any hyperintense signal within them.

1:23

And some of them look a little bit brighter

1:25

in signal when you compare it to the BOD,

1:27

but for the most part, they're really not T1

1:28

hyperintense, as we can see over here.

1:33

We'll give contrast to get a sense of what

1:34

this looks like, and what you notice quite

1:38

readily is that many of them enhance, right?

1:42

Gallstones should not enhance, and so some of these

1:44

are going to be gallstones that are not enhancing.

1:46

Perhaps these cluster over here, but a lot of

1:49

these other findings show definite enhancement.

1:51

For example, this one here shows enhancement.

1:54

And so that's not a finding

1:56

that is seen with gallstones.

1:59

And so you're left with multiple filling

2:02

defects, many of them round, protruding into

2:05

the lumen of the gallbladder, looking like they're

2:08

attached to the wall, about the same size.

2:11

Any of these enhance; this is a characteristic

2:14

imaging appearance of cholesterol polyps.

2:19

Now if we take a step backward and talk about

2:21

the word "polyp" per se and gallbladder polyp,

2:24

it's really, um, a mass that can be either polypoid

2:27

in its shape or maybe more sessile in its shape that

2:31

protrudes from the gallbladder mucosa into the lumen.

2:35

We can classify them into two big categories:

2:38

neoplastic polyps or non-neoplastic polyps.

2:42

An example of a neoplastic polyp would be an adenoma.

2:45

And some of these may be pre-malignant. Non-

2:48

neoplastic or not pre-malignant, and examples

2:50

include inflammatory polyps, as well as cholesterol

2:53

polyps that you can see in this example.

2:56

Now, overall, it's difficult to differentiate

2:59

different types of polyps on imaging.

3:02

However, when they're small in size, typically

3:04

less than 10 millimeters, and they're multiple,

3:06

as can be seen in this case, they have

3:08

a relatively round or polypoid appearance.

3:10

These are all signs of benignity.

3:12

So when I see that, I can reassure

3:14

my providers that, whereas I can't

3:17

with a 100 percent degree of confidence

3:19

differentiate benign from malignant

3:21

polyps, this has a benign appearance.

3:24

And the good news is that when you look at all types

3:26

of gallbladder polyps, cholesterol polyps, which are

3:29

non-neoplastic polyps, are the most common.

3:31

So statistically speaking, when you have a

3:34

gallbladder polyp, it's probably going to be

3:35

a cholesterol polyp, which is a benign polyp.

3:38

The question that really arises is, what do you do

3:41

when you see gallbladder polyps, knowing that you

3:43

really can't differentiate benign

3:47

from malignant lesions or pre-malignant lesions?

3:50

It's challenging.

3:51

And now there are some guidelines out there that

3:53

help us to decide what to do.

3:56

In general, if a polyp

3:59

is greater than or equal to 10 millimeters,

4:02

at the very least you should refer them to a

4:04

surgeon because, as it turns out, the larger the

4:06

polyp is, the more likely it may be malignant.

4:09

So refer them to the surgeon. If they

4:11

want to do a cholecystectomy, they can.

4:13

If they want to keep on doing

4:14

surveillance, that's fine as well.

4:16

As long as they keep a close eye on them,

4:17

particularly when they're more than 10 millimeters.

4:20

When they're between 6 and 9 millimeters, groups have

4:24

advocated for just surveillance at 12-month intervals.

4:28

If they're stable at that, you can potentially

4:30

monitor them yearly for a couple of

4:33

years to make sure they're stable in size.

4:35

If they're less than 5 millimeters, some

4:38

groups have advocated no follow-up, while some groups

4:40

have advocated serial follow-up, but without specific timelines.

4:42

In general, if they're more than

4:44

10 millimeters, get somebody to have a look

4:46

at them, potentially take out the gallbladder.

4:48

If they're less than 5 millimeters, it's probably okay

4:50

to just let it go.

4:53

Particularly if you have a patient who's not at

4:55

increased risk for developing gallbladder cancer.

5:00

If it's somewhere in between, they should

5:01

probably get some serial imaging to make

5:03

sure that these don't grow or become

5:06

larger or more invasive over a period of time.

5:09

But this, however, is a good example of multiple

5:11

small polyploid masses, many of which enhance,

5:15

and a very good example of polyploid

5:17

cholesterol polyps, benign, and the most common

5:21

type of polyps we see within the gallbladder.