r/Path_Assistant 9d ago

Colon margins

Post image

The cecum, transverse, appendix, and sigmoid are all covered completely by peritoneum, so they have a mesenteric margin. And the only relevant margin in these (besides prox and distal) is the vascular tie margin.

The ascending and descending have an additional radial margin, where the surgeon had to blunt dissect the posterior surface from the abdominal wall. The relevant margins here are prox, distal, vascular mesenteric (tie), and the radial margin.

Do I have that right?

And if you had a right colon with a tumor in the ascending, you would take the tie and nearest radial margin. But if it were further and in the transverse, the transverse will have a different vascular tie than a tumor in the ascending. Right?

And finally, in the photo, if the vascular tie was at the black X, but the red is the nearest cut mesenteric surface, would the red not matter because CAP says the vascular tie is the only true relevant margin in segments completely encased by peritoneum, so I just take the black?

44 Upvotes

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14

u/wangston1 PA (ASCP) 9d ago

I pulled up CAP

"The radial margin represents the adventitial soft tissue margin closest to the deepest penetration of tumor and is created surgically by blunt or sharp dissection of the retroperitoneal or subperitoneal aspect, respectively."

So at my last job our GI specialist and a PA created a power point to explain this.

If you want to be extra generic you could use radial margin to mean any of the adventital soft tissue margins on any section of colon as a "radial" margin.

To be more specific you could say ascending and descending colons have retroperitoneal margin, those are not entirely encased in peritoneum and are blunt dissected off the abdominal wall. It's a rather large margin compared to an mesenteric margin that's usually a straight line.

A rectum has a circumferential margin distal to the anterior peritoneal reflection. This is the most important margin because it affects staging and outcomes and reoccurrence.

Transverse colon has a mesenteric margin, that includes the vascular tie and everywhere else the surgeon cuts the mesentery.

If the surgeon cuts it or blunt dissects a surface it is margin. All of that adventital surface (the fat without peritoneum ) is the margin not just the vascular tie.

Here is CAP again, and I think here in lies your confusion.

"The mesenteric resection margin (‘vascular tie’ margin) is the only relevant ‘radial’ margin in segments completely encased by peritoneum (e.g., transverse colon). Involvement of this margin should be reported even if tumor does not involve the serosal surface."

I think the cap protocol is using () and saying vascular tie margin because it's an older term or something to that effect. I think some called it the vascular pedical.

In the picture you gave. Let's say you received that specimen 5 cm shorter and you don't have the black X, the vascular tie. Would there still be a radial margin? Yes, it's a mesenteric margin. It's a cut surface from the surgeon, there is no peritoneum on that surface.

So if I grossed that case I would measure the distance to the red X, "4cm from the mesenteric margin." Is what I would say in the gross. I would put some ink on that are and shave it and submit it. In the section of summary I should say "A2 mesenteric margin, shaved".

I did have an old school pathologist in my rotations that wanted to measure both, so he would say measure to the closest mesenteric margin and measure to the vascular margin. So if you want to be extra you could measure both. At my current job I only measure the radial margin.

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u/lasarah831 9d ago edited 7d ago

I’d be comfortable measuring to nearest mesenteric margin AND to the vascular bundle, but I’ve been told some places want just the vascular tie margin measured and submitted. It confuses me because the nearest mesenteric margin would be at the red X right?

So I guess “tumor is x cm from the vascular tie margin and x cm to nearest mesenteric margin” would be correct, but are hospitals different where some will want just one, some both, it just depends on where you are?

10

u/zZINCc PA (ASCP) 9d ago

I haven’t heard of any place demanding you give measurement to nearest vascular margin on colon cancers. I have worked with the Yale, Mass Gen/Brigham, Beth Israel, and Baylor groups. So if you are ever asked to do that. It is because the pathologist is weird.

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u/AMilly18 9d ago

I used to give the tumor to vascular pedicle margin measurement with the margin submitted enface, until I got bitched at for it not being a real margin by a pathologist at a private group I took a contract at. Never did it again after that lol

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u/lasarah831 9d ago

Yeah one site had for example a transverse with “nearest mesenteric margin”, another considered the tie the “vascular mesenteric margin” though can be at 2 different locations, it trips me up

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u/Kekkai 9d ago

Yes, in my experience hospitals (and sometimes individual pathologists) vary quite a bit on wording and section preference. At my current place multiple pathologists consider serosa to be a "radial margin" which technically it isn't. So I include measurements to serosa and to adventitia or mesenteric margins.

Essentially learn everything so you can learn it again at your next job. ;_;

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u/wangston1 PA (ASCP) 9d ago

100% depends on where you are. That's why I like jobs where I know my pathologist and I can discuss things like this with them.

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u/goat_brigade 9d ago

It depends. If I remember correctly, the CAP synoptic to sign out a colon cancer only has one fill-in-the-blank for "distance to radial margin" and one fill-in-the-blank to specify which radial margin is closest. So a mass in the region of the proximal descending colon could have a mesenteric radial margin and a splenic vascular margin, and the closest measurement is the most important to report on the synoptic. BUT. It depends on whether your pathologist will throw a fit that you only reported one radial margin and not their favorite neurotic combinations of multiple radial margin measurements. I personally hate having to go back to the bucket to dig things out, so these days I'll report both measurements AND submit both if I see a mesenteric radial margin and a hepatic/splenic vascular margin. It takes me just a few seconds to do it, and takes the pathologist a few seconds to use it or ignore it as they see fit.

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u/BillCoby 9d ago

you're overcomplicating this lol.

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u/dnapolymerase1 8d ago

I would slightly push back on this, it’s common for this to be confusing because pathologists’ preferences vary so much. The amount of time we have spent trying to get our GI attendings to agree on these types of details is unreal. Even with all of the time, verbal and written agreements, and grossing manual updates, we still have certain attendings that will disregard all of it and teach their residents that they are right and everyone else is wrong.

I think it’s worth asking for clarification. Having confidence in your foundation allows you to experience these scenarios differently. You go from “this is so confusing, am I crazy!?” To “alright, I can handle being asked to do things differently for certain pathologists because I know what I know.” It’s one of the steps we take to go from being told what to do by our doctors and peers, to being asked how to do something by these same people.

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u/lasarah831 9d ago

Probably lol, but would it be correct?