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This next case is a 60-year-old female who presents

0:04

with abdominal pain, for which a CT scan was obtained.

0:07

And so here we have a CT scan of the abdomen, performed

0:11

with intravenous and oral contrast, and we can immediately

0:14

see that there's marked biliary ductal dilatation.

0:16

As you scroll more inferiorly, there is a large,

0:19

hypodense mass, sort of centered in the portohepatic,

0:22

uh, but probably arising from the liver.

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Um, borders are pretty well-defined, but there

0:28

are portions of it that look a little bit complex.

0:30

For example, if you go along the lateral aspect, there's a

0:34

portion here that, uh, may or may not be part of the lesion,

0:38

but certainly looks like it has a more soft tissue appearance

0:41

than, uh, the, uh, more hypodense component of this mass.

0:44

And then even here, there's a very, very subtle area

0:47

that, of, um, hyperdensity that may reflect, uh,

0:50

a septation or a complex component of this mass.

0:53

And so, for this reason, an MRI

0:55

was ordered for further evaluation.

0:58

So we'll begin looking at our MRI as we do all

1:01

other liver MRIs with our T2-weighted sequences.

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Let's evaluate the liver lesion itself.

1:06

So here we have a T2-weighted sequence, this

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is a T2-weighted sequence with fat saturation.

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And again, this demonstrates this rather large mass

1:14

that's arising from the central portion of the liver.

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It's, uh, quite bright on the T2-weighted images,

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and on the turbo spin-echo sequence, also very bright.

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So we know that it's probably going to be a

1:24

cyst of some sort, but it's not a simple cyst.

1:27

As we look on the posterior aspect of it, we see that

1:30

there's a very, uh, discrete septation within it.

1:33

That's, um, slightly thickened, and as we score

1:36

more superior to it, we see that there's no

1:38

real correlation to that soft tissue component,

1:42

uh, that was suggested on the CT scan.

1:44

So if that were to be present, it'd be present in

1:47

approximately this location, so there's nothing

1:49

there that looks like a soft tissue component.

1:53

So we have to evaluate this on our remaining sequences.

1:58

You have to look at the T1 in and out of phase

2:00

sequence to see if there are any areas of fat or

2:03

increased susceptibility within this lesion.

2:05

So over here we have the in-phase sequence,

2:08

over here we have the out-of-phase sequence.

2:10

We know it's out of phase because you can see that India

2:11

ink artifact at the interface of the liver and fat.

2:14

And again, the lesion is pretty homogeneous and, uh,

2:17

really T1 hypointense on both sets of sequences.

2:21

And there are no areas of increased susceptibility on

2:23

the in-phase sequence, no areas of signal dropout

2:26

on the out-of-phase sequence that suggest fat.

2:28

So, uh, none of those contents are present.

2:31

We can't see along its posterior aspect.

2:33

There's a little, little bit of hyperintense T1

2:36

signal in both the in and out-of-phase sequences.

2:39

And so that may reflect hemorrhagic or proteinaceous debris.

2:41

We're going to have to evaluate

2:42

that on the post-contrast images.

2:45

And another thing to look at on the in-phase

2:47

sequence, we talk a lot about what, uh, you know,

2:49

whether a lesion has increased susceptibility.

2:51

We can actually see that adjacent to this

2:53

lesion on the in-phase images over here.

2:55

We can see a focal area of increased susceptibility.

2:58

Is T1 hypointense on the out-of-phase image becomes darker

3:02

on the in-phase imaging with a little bit of blooming

3:03

artifact, and that just represents cholecystectomy clips

3:07

in this patient who had a prior gallbladder surgery.

3:09

We'll then move on to the T1 pre-contrast image

3:12

to assess, uh, the T1 signal of this lesion.

3:16

And on this sequence, we can see that it's fairly

3:18

homogeneously T1 hypointense except for that area

3:21

posteriorly that has very linear hyperintense T1 content.

3:26

So that may reflect some debris that's just sort

3:28

of layering over there, could represent soft

3:30

tissue that enhances, so we're going to have

3:32

to look at that in our post-contrast sequences.

3:35

So here we have our post-contrast sequences

3:37

and because of the presence of that T1

3:39

hyperintense content, I'm going to skip.

3:44

Focus right over here on the arterial phase images.

3:47

We can see that there are no nodular

3:49

components of enhancing tissue.

3:52

Certainly, that T1 hyperintense component is not enhanced.

3:55

In that similar location, there's a very,

3:56

very thin septation within this lesion.

3:59

Similarly, on the portal venous phase, no

4:00

areas of solid enhancement, just a few thin

4:02

septations seen over here and seen over here.

4:05

And finally, on the equilibrium phase images,

4:07

again, just thin septations, which, uh, which

4:10

enhance over here without a solid component.

4:14

To summarize, we have this large cystic lesion

4:17

within, uh, the central portion of the liver.

4:20

Uh, no solid enhanced components within it,

4:21

but there are a few septations you can see.

4:23

Some, uh, T1 hyperintense content.

4:25

That's probably hemorrhagic or proteinaceous debris.

4:28

The borders of this lesion appear a little bit lobulated.

4:31

And it's causing some degree of biliary ductal dilatation.

4:34

So in and of itself, this is a nonspecific finding.

4:37

If you combine this with the patient demographics

4:40

of a 60-year-old female, have to think about this

4:43

entity, which is now known as hepatic mucinous cystic

4:47

neoplasm, formerly known as biliary cystadenoma.

4:53

Now, these are uncommon entities most often seen

4:56

in, uh, females from ages of 40 to 60 years old.

5:00

And, uh, it's composed of mucin-producing epithelium, and

5:04

it's associated with an ovarian-type subepithelial stroma.

5:08

As I said, it was previously classified as

5:10

either a cystadenoma or a cystadenocarcinoma

5:16

when it had a more malignant component.

5:17

Now it's simply known as either a non-epithelial stroma.

5:21

invasive hepatic mucinocystic neoplasm or

5:26

an invasive hepatic mucinocystic neoplasm.

5:30

Complications of the non-invasive hepatic mucinocystic

5:32

neoplasms include infection, potentially rupture, over

5:37

time this, a non-invasive, uh, lesion could become

5:40

invasive when you see more solid enhancing components

5:44

and oftentimes when it gets this large you want to have

5:47

the patient undergo resection, particularly when it's

5:49

causing mass effect and causing biliary ductal dilatation.