0:01

So this is a male patient in his 70s with

0:03

elevated liver function tests, as well as

0:05

pain, and got a CT scan with intravenous

0:08

contrast to further evaluate this.

0:10

And as we scroll through these

0:11

images, let's focus on the liver, and

0:15

specifically the intrahepatic bile ducts.

0:18

We notice that the intrahepatic

0:19

bile ducts are dilated.

0:20

We know what that looks like.

0:22

And really the ducts that are dilated are

0:25

preferentially in the right hepatic lobe.

0:29

The right hepatic lobe ducts are dilated.

0:30

The extrahepatic bile

0:31

tree is hardly even perceptible.

0:33

It's probably this little small

0:34

portion here looks normal.

0:37

Some of the left ducts may be a

0:38

little bit bigger than you would

0:40

like, but generally look okay.

0:42

The right hepatic ducts are

0:44

where the abnormality is.

0:45

Let's look at this finding on

0:46

the coronal weighted images.

0:48

And it shows you the same thing of how

0:50

the ducts are dilated on the right side.

0:52

Now one of the things that, you know, if you

0:54

look at this very critically, not only are

0:56

the ducts dilated on the right, but there are

0:59

potential filling defects inside these ducts.

1:02

I'm going to magnify on some of these ducts, and

1:04

you notice that maybe there's something in here.

1:06

Maybe there's something in here.

1:07

The density inside these bile ducts is not

1:09

uniformly low dense as you would expect,

1:12

you know, bile to appear like on CT scans.

1:14

In fact, there's heterogeneous density

1:16

with areas that are relatively brighter.

1:18

If you look on the coronal image, I

1:19

think you can probably see this a little

1:21

bit better, and I'm going to window it.

1:24

You notice that this looks fairly hypodense,

1:27

but as you go out in the periphery, right

1:29

over here, it looks like there's some

1:30

hyperdense content inside this bile duct.

1:35

And so we're thinking about

1:37

what this could represent.

1:38

We've certainly seen one case already,

1:40

something called recurrent pyogenic cholangitis

1:43

where we saw perhaps something similar, but

1:46

involving the lateral left hepatic lobe.

1:49

And it turns out when you have a recurrent

1:50

pyogenic cholangitis, it prefers going

1:54

to the left lateral hepatic lobe,

1:55

that's one of the classic locations.

1:57

But the posterior right hepatic lobe is

2:01

also very similar, and this in fact would

2:01

be deemed the posterior hepatic lobe.

2:02

So if you look at this and you say, okay, I

2:04

have ducts that are dilated predominantly in

2:07

that posterior right hepatic lobe distribution

2:09

with potential filling defects, which

2:11

may reflect small pigmented stones.

2:13

Could this be recurrent pyogenic cholangitis?

2:15

I think that would be a not an

2:17

unreasonable way to approach it.

2:19

In fact, it would be a very

2:19

reasonable way to approach it.

2:21

Let's look at the MR to see if we have any

2:22

other clues to figure out what this could be.

2:24

I'm going to start off by looking at the T2 and

2:27

the T1 and the coronal T2 image I'll put up here.

2:30

So it's not showing us anything new in

2:33

that we're going to see ducts that are

2:34

dilated, right, in the posterior right

2:37

hepatic lobe, predominantly the extra

2:38

hepatic biliary tree is within normal limits.

2:40

The left hepatic ducts are fairly okay.

2:43

We do notice that there are filling

2:45

defects within these ducts.

2:48

We can perhaps appreciate them better on the MR.

2:51

All these intermediate signal

2:53

abnormalities inside the ducts themselves.

2:56

Now remember, stones, which is something

2:59

you could see with recurrent pyogenic

3:01

cholangitis, have an appearance

3:03

that is T2 hypointense, quite dark.

3:06

It would look as dark as this signal over here.

3:09

This doesn't quite look like that.

3:10

This almost has this very

3:11

soft tissue appearance.

3:12

In fact, if anything, it looks

3:13

very similar to the spleen.

3:14

If you look at the coronal images,

3:16

you can again see that there is

3:18

this intermediate signal that's filling up a

3:20

lot of these posterior right hepatic ducts.

3:23

So that becomes interesting

3:24

and what this could represent.

3:26

Let's look at it on the T1s.

3:28

Signal is fairly hypointense, not quite as

3:31

dark as bile, but the internal signal inside

3:34

the T2 intermediate signal is fairly

3:36

hypointense; it's certainly not hyperintense.

3:39

And when we give contrast, we

3:41

can see the content inside those

3:44

bile ducts is in fact enhancing.

3:46

This is a bile duct that's not

3:47

enhancing, right, because it contains

3:49

bile, but look at this stuff here.

3:52

These are all dilated bile ducts, but

3:53

the inside of them is enhancing, and

3:55

that corresponds to that intermediate

3:58

signal we saw in the T2 weighted images.

4:00

And so this is, again, seen, I

4:02

think, nicely on the coronals.

4:03

Look how much it's enhancing

4:05

inside the bile ducts.

4:06

There's actual tissue, there's tumor

4:08

tissue inside the bile ducts that

4:09

is enhancing, and these bile ducts

4:11

are all dilated associated with that.

4:14

So this needed to be resected, needed

4:16

to be treated and was taken out

4:17

and this turned out to be a biliary

4:20

intraductal papillary mucinous neoplasm.

4:24

I wanted to show this entity because this is

4:27

a very uncommon entity, but it's something

4:29

that's being written about a lot more commonly.

4:33

This essentially amounts to a mucin-producing

4:35

neoplasm that arises from the bile ducts.

4:39

The imaging appearances that

4:40

have been described with this

4:42

is that there's almost aneurysmal

4:44

dilatation of the bile ducts.

4:46

It's often segmental as seen in this case

4:50

and they contain enhancing masses that

4:52

are polypoid or nodular in appearance.

4:55

You can have biliary ductal dilatation proximal

4:58

to this and even sometimes distal to this

5:01

due to mucin secretion from this tumor itself.

5:04

And overall though, it's quite difficult

5:06

to differentiate from a cholangiocarcinoma.

5:09

I think if you saw this and thought

5:10

this was a cholangiocarcinoma,

5:11

you would not be faulted for it.

5:14

However, when you see this sort of focally

5:16

aneurysmal dilatation of bile ducts with sort

5:19

of polypoid nodular enhancing internal tissue,

5:22

you've got to think of an intraductal papillary

5:24

mucinous neoplasm.

5:25

You may, you know, I don't say you've

5:27

got to, because it's an uncommon

5:28

entity, but one thing you should think

5:30

about is, could this represent a biliary

5:34

IPMN, intraductal papillary mucinous neoplasm?115 00:04:00,454 --> 00:04:02,035 And so this is, again, seen, I

4:02

think, nicely on the coronals.

4:03

Look how much it's enhancing

4:05

inside the bile ducts.

4:06

There's actual tissue, there's tumor

4:08

tissue inside the bile ducts that

4:09

is enhancing, and these bile ducts

4:11

are all dilated associated with that.

4:14

So this needed to be resected, needed

4:16

to be treated and was taken out

4:17

and this turned out to be a biliary

4:20

intraductal papillary mucinous neoplasm.

4:24

I wanted to show this entity because this is

4:27

a very uncommon entity, but it's something

4:29

that's being written about a lot more commonly.

4:33

This essentially amounts to a mucin-producing

4:35

neoplasm that arises from the bile ducts.

4:39

The imaging appearances that

4:40

have been described with this

4:42

is that there's almost aneurysmal

4:44

dilatation of the bile ducts.

4:46

It's often segmental as seen in this case

4:50

and they contain enhancing masses that

4:52

are polypoid or nodular in appearance.

4:55

You can have biliary ductal dilatation proximal

4:58

to this and even sometimes distal to this

5:01

due to mucin secretion from this tumor itself.

5:04

And overall though, it's quite difficult

5:06

to differentiate from a cholangiocarcinoma.

5:09

I think if you saw this and thought

5:10

this was a cholangiocarcinoma,

5:11

you would not be faulted for it.

5:14

However, when you see this sort of focally

5:16

aneurysmal dilatation of bile ducts with sort

5:19

of polypoid nodular enhancing internal tissue,

5:22

you've got to think of an intraductal papillary

5:24

mucinous neoplasm.

5:25

You may, you know, I don't say you've

5:27

got to, because it's an uncommon

5:28

entity, but one thing you should think

5:30

about is, could this represent a biliary

5:34

IPMN, intraductal papillary mucinous neoplasm?