0:00

All right. So, this is a 47 year old

0:03

patient with biopsy proven rectal cancer presenting

0:06

for primary staging MRI. Let's look

0:09

at

0:11

Some images here that are relevant. So I'll

0:14

just point out the tumor for you. So this is not as easy to see as

0:17

some of the other ones but here's a normal rectal wall here

0:20

and then we get into some thickened areas here. There's

0:23

a couple of raised World edges. So this is a mid to

0:26

high rectal cancer.

0:29

And I just wanted I want you to take a look at.

0:33

The coronal and axial obliques here. So again,

0:36

I'm going to ask you about t staging and

0:39

end staging and then I'll ask you a couple of other questions.

0:44

So let me just go through the teacher oblique.

0:47

Sorry the coronal is it

0:50

cool?

0:51

Okay, so there's a really nice look at the tumor here.

0:57

And then come on. All right. So let's

1:00

look at T stage when you guys think this T stage is

1:03

here.

1:10

I'll try to put it on some representative images to help you out.

1:16

So clearly by the choices. This is a more advanced tumor than

1:19

the other ones that we saw.

1:23

And I will give you a bit more information.

1:27

Okay, so, let's see what people thought.

1:29

Okay. So yeah, so

1:32

it's kind of it was definitely a spread. So let's

1:35

go over the the staging. So the T3 staging

1:38

is broken down into four sections. So T three

1:41

a is less than one millimeter depth

1:44

of invasion B is one

1:47

to five millimeters C is five to 15 millimeters

1:50

and D is greater than 15 millimeters. So in

1:53

this case because you didn't have a measurement it's hard

1:56

to judge. Exactly. So certainly if you picked t3cd

1:59

that's very reasonable A

2:02

or B would mean that there's between one

2:05

to five millimeters of extension deep to the

2:08

musculars. This is probably a bit more than that. I think we got about seven

2:11

or eight millimeters in this case. So this is a t3c /

2:14

C. It's not a T4 because it's

2:17

not contacting one of the adjacent vistara

2:20

like you would need for a T4.

2:23

So you need to have contact of the bladder or the prostate

2:26

gland or the peritoneal reflection for it

2:29

to

2:29

T4 lesion, so this is a t3c

2:32

/ d

2:34

Okay, and now the next question has to do with again

2:37

n stage. So what do you think the end stage

2:40

is in this case based on the images that I'm showing

2:43

you so I'm not showing you a large field of view because it's

2:46

not really relevant but based on this. What do

2:49

you think the end stage is?

2:55

And this would be one that you'd probably want to scroll through.

3:00

Just to get a sense of what's going on. So

3:04

Um, you know just do the best you can I'll try and show you

3:07

the relevant images here.

3:12

Okay.

3:14

All right. So so we have everything from

3:17

one suspicious node to three suspicious

3:20

nodes to tumor deposits. Okay. So there's

3:23

at least two suspicious structures

3:26

here. So there's this one.

3:29

And there's this one. So now the question

3:32

is what are these and this is one of the reasons I wanted to

3:35

show this case. So here's structure

3:38

a

3:40

Which is clearly abnormal.

3:43

and then

3:45

here is structure B, which also

3:48

looks at normal. So why is this abnormal? Well one

3:51

this is spherical two look

3:54

at the signal intensity normal appearing

3:57

lymph nodes usually have a fatty hilum or they're

4:00

very Bland looking with the signal. This has

4:03

an area of low 22 signal within

4:06

it which is clearly abnormal and it's heterogeneous. So

4:09

the whole thing is in dark, there's some intermediate signal

4:12

and some low signal and one teaching point.

4:15

I just want to mention is quite often in the pelvis

4:18

right around here around the side walls. You might

4:21

see little structures that are low T2 and spherical

4:24

down here. So just be aware that we both

4:27

can fool you and that's a pitfall of MRI

4:30

because if you have a calcified flavorless that

4:33

looks spherical as most of them do you might get

4:36

tricked into thinking that it's an abnormal node. So always check

4:39

back with your CT to see if it's vascular in nature

4:42

rather than calling a lymph node, but this is clearly something.

4:45

Animal whether a lymph node or tumor deposit is a

4:49

challenge. So let's put up the next question. So this

4:52

is structure a

4:56

so which of the songs this is a challenging forward type

4:59

question, so

5:01

Apologies for that, but which of the following is incorrect comparing

5:04

to structure a so, I think I'll put up structure.

5:09

See over here so we can oh shoot.

5:12

It's gonna link them. Okay, so I'm just going to

5:15

have to scroll through so

5:21

okay, so there's structure a

5:24

Okay, so take a look at that. And then the other one is

5:27

structure B here.

5:29

So what do you think the difference is? What does a have

5:32

that's different to be so which of these is incorrect about

5:35

a does it contain? It does

5:38

not contain mucine. Is that incorrect?

5:41

It likely contains lymph node architecture. Is that

5:44

correct or incorrect?

5:46

Malignant cells or poor prognosis. So

5:49

which of these is incorrect about this structure here?

5:52

So we know it's abnormal. What do we think it is?

5:54

In which of these is incorrect?

6:02

Good job. Likely contains lymph node. Architecture. Very

6:05

good. Yeah, so this is actually a tumor deposit.

6:08

So I wanted to show this because it's a really nice example

6:11

of what a tumor deposit looks

6:14

like so let me just backtrack a little bit. It's very

6:17

difficult to distinguish on Imaging between

6:20

tumor deposits and lymph nodes and currently ajcc

6:23

groups them together.

6:26

So you saw in one of the last questions. We had n1c as

6:29

a category which means tumor deposits,

6:32

but we're starting to learn that these are distinct

6:35

from lymph nodes. And

6:38

what we think is the best way to

6:41

differentiate between them on Imaging is whether

6:44

or not these lesions are

6:47

interrupted by the course of obey or a vessel. So

6:50

you can see in this case. Here's the tumor extending deep to the

6:53

muscularis and then if you follow the vessels,

6:56

In our next to it they end up in this spherical

6:59

looking structure and that's what we're looking for to determine

7:02

whether or not there are

7:05

tumor deposits.

7:06

In terms of this structure here. Could it

7:09

be a tumor deposit? Yes, it certainly could it could also be a

7:12

lymph node, but this one because of its location because of its

7:15

proximity to the vessels where pretty certain

7:18

that this is actually a tune deposit. And now why is

7:21

it important to distinguish between lymph nodes and tumor deposits? Well

7:24

patients who have tumor deposits are actually

7:27

at risk for a worse

7:30

prognosis than those with lymph nodes. So that's the reason

7:33

why the rectal cancer Community is

7:36

moving towards separating those two entities. So

7:39

again, I'm part of an essay

7:42

our panel on lactal cancer. So we're just

7:45

in the process of changing our synoptic report so

7:48

that we separate lymph nodes from tumor deposits.

7:51

So it's much clearer to the referring physician that hey

7:54

this patient may have a poor prognosis. So

7:57

let's just, you know, see if if there's

8:00

a management plan that's more appropriate.

8:03

So keep this in mind, so some people have asked is

8:06

emvi related to tumor deposits

8:09

and we don't quite have an answer to that yet. We

8:12

don't know if the tumor deposits are spread by the

8:15

vascular root or potentially lymphatic. So

8:18

that's a question. We're still trying to answer but if

8:21

you see this convergence of vessels towards an

8:24

abnormal looking structure in the meso rectal

8:27

fat then always flag that as a

8:30

potential tumor deposit because it really can affect the outcome

8:33

of the patient with a worse problems.

8:36

Okay, so good job on that.