0:00

So the next case is going to be an MRI.

0:04

So most of these cases are MRI,

0:05

but I've thrown in a few CT's just to sort of show you some cool cases.

0:10

And this one is one case I will apologize for

0:13

in the sense that this is done at an outside institution.

0:16

And I don't have all the sequences

0:17

available for you, but I will show you a few choice sequences.

0:21

In those, I'm hoping that it's enough for you to make the right diagnosis.

0:26

So I'm going to start off with T2 weighted images.

0:28

I always like looking at MRIs with the T2 weighted images.

0:31

And you know, the finding I actually want you to focus on this case is really

0:36

at the bottom half of these T2 weighted images over here.

0:40

So this is a T2 weighted nonfat saturated sequence.

0:43

There's finding right over here.

0:44

So I just want you to focus on that for a second.

0:48

You can see the bladder filled with fluid

0:50

and there's a finding associated with it over there.

0:53

I'm going to then switch to T2 fat saturated images.

0:57

and we're going to scroll through the bladder to show you that finding a little bit nicer.

1:01

So you can see the bladder over here.

1:03

You can see the finding over here, in the bladder.

1:07

Sort of relatively exophytic mass.

1:12

Notice the T2 signal within it.

1:14

I'm going to show you the mass again on the sagittal T1 weighted images.

1:21

This is pretty contrast over here.

1:25

You can see the mass, notice the signal associated with it.

1:30

And I'll show you the same lesion on the post contrast sequence right over here.

1:38

All right. So let's do this sort of layout

1:42

so you get a sense of all the sequences that we looked at.

1:45

I apologize on the T2, you just sort of see it there,

1:48

but you see it much nicer on the T2 weighted images with fat saturation.

1:52

And you can have another look at it

1:55

on the T1s pre and post, where you get a sense of what the signal

2:01

of this mass looks like and where the locations of these masses as well.

2:04

That might become important to the discussion that we're going to have.

2:10

All right. So if everyone is pretty good

2:14

has had a chance to assess this lesion, let's go on to the second question.

2:20

So for this one, again,

2:22

like the first one, I'm asking for the most likely diagnosis.

2:25

And so I'm presenting with you four

2:27

histologies that can occur in the bladder, some more common than others.

2:34

Some have specific associations, some have specific appearances and

2:39

sort of asking for your help to figure out if you have to give a diagnosis.

2:44

And it's easy to say this is a bladder mass, right?

2:47

We can all do that.

2:48

But if we can sort of push it to the next level and really tell the referring providers,

2:53

"This is not only a bladder mass, but this is what I think the histology is."

2:57

I think then we can start to add some value.

3:02

So Adenocarcinomas, Leiomyoma, Paraganglioma and Squamous cell carcinoma.

3:11

Alright.

3:12

So we are neck and neck with leiomyoma and squamous cell carcinoma.

3:17

No one picked paraganglioma and adenocarcinoma.

3:20

We have one option over there.

3:23

So that's very good.

3:24

So let's start going through this lesion.

3:25

And so I sort of described this lesion a little bit already.

3:29

So in the T2 weighted images without fat saturation,

3:32

you sort of just see it at the corner.

3:34

But what I want to sort of show you here

3:36

is that there's relatively dark T2 signal. Right?

3:38

So that's going to be important for us

3:41

to try to figure out what we think the histology is going to be.

3:44

On the T2 fat saturated images, we can see that dark signal is maintained.

3:48

And the reason I wanted to show you this one

3:50

and this one as well, is because if I only showed you this one,

3:53

there is possibility you thought that, hey, maybe this lesion contains fat

3:57

because this is a fat saturated image and it's dark.

3:59

But that's not the case.

4:01

This lesion was dark to begin with on the non fat sequence.

4:04

Alright? So this is a T2 hypointense mass. We can look at on the T1s,

4:08

I don't think it's as useful to look at on the T1s.

4:11

We can certainly look at it,

4:12

I think sort of intermediate signals similar to muscle, I would say.

4:17

But I think what's really telling both on the T2 and T1 weighted sequence is

4:20

it's really sort of homogeneous.

4:22

The borders as well are somewhat lobulated, right?

4:24

This is not necessarily an aggressive looking tumor,

4:29

at least based on these borders, where it's sort of infiltrative

4:31

and hard to sort of separate from the surrounding fat.

4:36

And what do we see on the post contrast sequence?

4:38

Again, very homogeneous and brisk enhancement that's associated with this.

4:42

The other thing I want to sort of point out with this

4:44

is that if you look at the epicenter of this lesion.

4:45

If I were to sort of draw

4:47

just a pinpoint where I think the region is originating from,

4:50

it looks like the center of the lesion is

4:52

aligned with sort of the wall of the bladder and most of it is growing

4:55

exophytically with some of it also sort of growing endophytically into the bladder.

5:00

And so, you know I like this case because it's sort of an uncommon case.

5:04

You don't see it that often, but when you see a mass in the bladder

5:08

that has this homogeneous signal that is really dark T2 hypointense

5:11

with homogeneous enhancement, you got to think of the possibility

5:14

of bladder leiomyoma, which is the answer in this instance.

5:19

So as uncommon as this tumor is,

5:21

it's actually the most common mesenchymal tumor of the bladder.

5:25

They're often small and incidental. I forgot the history of this patient,

5:29

but this is on the smaller side, and the location is often intramural.

5:35

So again, that if you looked at the center,

5:36

epicenter of this lesions, probably along the wall

5:39

of the bladder itself, the smaller they are,

5:42

the more homogeneous they are.

5:44

The larger lesions, as you can imagine, can become a little bit more

5:47

heterogeneous, just like leiomyomas anywhere.

5:50

For example, the uterus,

5:51

it can undergo cystic degeneration when they become very large.

5:55

These are benign. They don't have a malignant potential.

5:58

They do need to be excised,

6:00

primarily because you're not really sure 100% that's what it's going to be.

6:04

But you have this appearance that's

6:07

certainly something you can suggest as the top in your differential diagnosis.

6:11

Now, the other option that we had,

6:12

adenocarcinoma was one of the options, and I don't blame that somebody picked it

6:18

because they thought, look at the location of this.

6:20

It's right sort of where you'd expect the urachus to be.

6:23

And adenocarcinomas are the most common cancer arising from the urachus

6:28

I think it's a good thought.

6:30

However, the appearance of adenocarcinomas

6:31

are much more heterogeneous as opposed to this one, where it's a lot more

6:35

homogeneous, often wall thickening, those tend to be aggressive tumors.

6:39

Adenocarcinomas as a side, as you all may recall,

6:42

are the tumors that are often associated with bladder diverticulum as well.

6:45

So if you see a bladder diverticulum in a mass,

6:47

you got to think of adenocarcinoma.

6:49

A squamous cell cancer.

6:50

A lot of people thought of that as well.

6:51

And I think that's, again,

6:53

not an unreasonable thought. As you may recall, it's the sort of tumor

6:56

that's associated with mucosal irritation of the bladder.

6:59

So whether it's chronic UTI,

7:03

long term indwelling catheters, schistosomiasis is classically associated

7:07

with squamous cell cancer. That's when you have to sort of think about it.

7:11

Now on imaging, often isn't sort of this lobulated homogeneous mass.

7:15

It's sort of manifests like a plaquelike

7:18

mass with thickening and very irregular borders.

7:20

The signal itself as well tends to be more intermediate in its signal.

7:24

That is, it's going to be brighter

7:26

in signal on the T2 fat saturated images than what I'm presenting over here.

7:30

And nobody picked paraganglioma, which is great.

7:32

It's a very heterogeneous mass, it tends to be hypervascular,

7:35

and it presents with a very classic sort of clinical symptom.

7:39

Does anyone in the chat box want to write

7:43

in what the classic symptom of a bladder paraganglioma is?

7:46

Okay, it means that maybe no one's recalling it right now.

7:49

But bladder paragangliomas often present with post-micturition syncope.

7:53

We have a patient who has this sort of symptoms and they get the imaging study

7:58

and you look at the bladders, it is heterogeneous hypervascular mass.

8:01

Think about it, bladder paraganglioma.

8:03

Another very uncommon lesion, but this case turned out to be bladder leiomyoma.

8:06

A bladder leiomyoma path proven T1 imaging here is homogeneous.

8:11

T2 hypointense briskly enhancing intramural location,

8:14

non aggressive appearing.

8:15

Think about bladder leiomyoma.

8:19

All right, excellent.

8:21

So let's go on to our third case.