0:00

Okay, let's take a 62-year-old man with a PSA

0:04

level of 41.32 in December of 2017 and then a PSA

0:12

that rose to 53.97 nanograms per mL on 2-26-18.

0:20

The patient has had two negative prior

0:23

biopsies, one in 2014 and one in 2015.

0:29

So our purpose in illustrating

0:31

this case is twofold.

0:35

One, to illustrate the pitfalls of very far

0:39

anterior cancers and how they can blend in,

0:42

even on MRI, with the anterior fibromuscular

0:47

stroma, and as a subset of that, be very

0:49

difficult to access biopsying the gland from

0:54

the back because they're so far anteriorly.

0:57

The second thing I want to do is

0:58

once again illustrate T staging.

1:00

So let's talk about T staging for a moment.

1:04

You know, a TAT one stage is a clinically

1:08

in apparent cancer, a T two stage, just for

1:12

basic, basic, it's confined to the gland,

1:14

and then you can break that T two stage

1:16

up into T two A, T two B, and T two C.

1:20

Uh, an A involves one half of one lobe.

1:23

A B involves more than one half of one lobe,

1:26

and a C involves both sides of the gland.

1:30

So both lobes, a T three.

1:34

A T3 extends through the prostate capsule.

1:38

You've got a T3A, which can be unilateral

1:41

or bilateral capsular extension, and a

1:45

T3B, which invades the seminal vesicles.

1:48

And then you've got a T4, where the tumor

1:50

is fixed or invades the seminal vesicles.

1:53

Uh, adjacent structures other than the

1:55

seminal vesicle, like the external sphincter,

1:57

the rectum, the bladder, the levator

2:00

muscles, the pelvic sidewall, and so on.

2:03

Now you could also assess the status of regional

2:06

nodes, as we've discussed in other vignettes.

2:09

And you can look for distant metastases, so that

2:12

would give you your N stage and your M stage.

2:15

Go to those vignettes for

2:17

assessment of those criteria.

2:19

So let's take this case.

2:21

We scroll axially, and there should be

2:23

a thin lentiform fibromuscular stroma.

2:26

How thin should it be?

2:28

Maybe 6, maximum 8 millimeters.

2:30

So it might look like this.

2:34

But it shouldn't really look like this.

2:39

There's just too much charcoal-like

2:43

smearing, dark signal intensity anteriorly.

2:46

Now you might say to yourself,

2:47

well, okay, how much is too much?

2:50

Well, I've given you a number.

2:52

But don't get so fixed on the number.

2:54

You know, maybe there are some people that

2:55

have a 9 mm anterior fibromuscular stroma.

2:59

Maybe they have a 3 mm.

3:01

So, let's use what's available to us.

3:04

So, let's go to the coronal, which is probably

3:06

going to be the least useful projection,

3:08

because we're tangent to, or parallel to the tumor,

3:12

but it's awfully smooth and gray, charcoal-like.

3:15

That's a bit disturbing.

3:18

Let's go to the sagittal where it might be more

3:20

helpful because we're going to be perpendicular to

3:22

this potential crossing side-to-side tumor that is

3:27

blending with the anterior fibromuscular stroma.

3:30

And there it is.

3:32

Oh, it's not just lentiform side-to-side.

3:35

It's lent to form up and down.

3:37

Here it is.

3:38

It goes all the way from here, to here, to here.

3:44

Oh, it's a lot bigger than it

3:45

looked in the sagittal projection.

3:46

The sagittal was very helpful.

3:48

And we have more than two centimeters of anterior

3:54

capsular contact with bulging anteriorly.

3:58

So you should at least suggest the

4:00

possibility of micro-invasion of the anterior capsule,

4:04

which would make this a potential.

4:08

T3 lesion.

4:10

Now what else can we use to supplement

4:13

our suspected diagnosis of a cancer and a

4:17

PSA 5, meaning it's greater than 1.

4:20

5 centimeters, in fact, cranial

4:21

caudate was well over 2 centimeters,

4:25

and I would use the diffusion image.

4:27

So let's go to it.

4:29

I wouldn't use the dynamic contrast-enhanced MRI.

4:32

That's probably my least favorite.

4:34

Favored nation sequence.

4:37

Let's go to the diffusion image, the B1600

4:41

image, and right there, in the area we

4:43

were suspicious, let's blow it up and make

4:45

it bigger, we have diffusion restriction.

4:49

There it is.

4:50

Let's scroll it.

4:52

It's on multiple axial sections because

4:55

it goes all the way up and down the

4:57

base and apex of the anterior gland.

5:00

Let me show you a B value that is zero.

5:03

You really don't see anything, do you?

5:07

Let me show you a B value that

5:09

is 50, really don't see much.

5:13

When you go to the higher B value, say 1200, and

5:17

then to 1600, the cancer is diffusion-restricting

5:23

and separated from the rest of the gland.

5:26

Let's compare it with the ADC map in which

5:28

the signal intensity should be low, and it is.

5:31

And we can scroll that and see the volume of

5:34

cancer and potentially trace it on the T2.

5:38

And the diffusion-weighted image.

5:41

Now let's go back to the morphologic

5:43

image for a moment, and I'm just going

5:44

to one up it, and let's make a survey.

5:48

Now some of you may like to have a T1-weighted

5:52

image, or a 3D T1 appearing image, such as a

5:57

T1 GRE, with thin slices, to look for nodes,

6:01

and separate them out from vessels, and look

6:04

for bony metastases, and other morphologic

6:07

abnormalities, and that's perfectly reasonable.

6:09

You could also use a high-quality T2

6:12

to do that, although it's not as easy.

6:14

But if you're very experienced,

6:16

you can use the T2.

6:17

Let's do that, and what are we looking for?

6:20

We're looking for solid, round objects

6:24

that don't have a fatty hilum in them.

6:26

And they're not tubular.

6:27

So let's keep scrolling.

6:29

And I see some flow voids in

6:31

the femoral artery and vein.

6:33

And I see a gray oval or

6:37

round structure on both sides.

6:40

And it's too big, and it's too bulbous, and it's

6:44

too juicy, and it's got a convex outer border.

6:48

It's not crinkled.

6:50

Most nodes that are benign look like this.

6:52

They kind of have this crinkly look to them.

6:55

And in the center, they'll

6:56

have a little bit of fat.

6:59

No fat, not crinkly, very bulbous,

7:04

and in this case, bilateral.

7:07

This is regional lymphadenopathic

7:10

involvement by prostate cancer.

7:13

So if we were going to stage this, we would

7:16

give this an N1, N0, no nodes, N1, regional nodes.

7:22

And then if we had distant metastases,

7:24

we'd go into our M staging.

7:26

So this case is illustrative of two,

7:30

perhaps three, key teaching points.

7:33

One, that antero-apical lesions can

7:36

blend in with the anterofibromuscular

7:38

stroma and easily get missed on imaging.

7:42

As a subset of that, two, Biopsying the gland

7:46

from the back may not make it easy for the

7:50

surgeon to access this very far anterior tumor.

7:56

And three, when you're T staging these

7:59

lesions, evaluate the capsule on both sides,

8:02

and do not forget to evaluate the

8:05

skeleton and the other associated accessory

8:10

structures in the neighborhood,

8:12

like the seminal vesicles, like the capsule,

8:15

like the regional lymph nodes,

8:17

which were positive in this patient.

8:19

And for those of you that were dialing in

8:22

and watching everything, there is a huge

8:25

cyst in the testicular region, an epididymal cyst,

8:29

which is gigantic on the film edge.

8:33

This is an example of a PI-RADS 5 in the

8:37

anterior fibromuscular stromal region, both at

8:41

the apex, at the middle of the gland, and the

8:43

base of the gland, running all the way anterior,

8:47

up and down with suspected capsular microinvasion.