Colon dysplasia Dr. Andy Connolly shows Sal what cancerous colon tissue looks like
- This is Sal, and I am still at Stanford Medical School with Dr. Connely.
- C: "Sal, we're going to continue. Sal, you're going to have to get one unit of credit for today."
- S: "Oh, my mother would be proud!"
- C: "So, what we're looking at today is a colon polyp."
- S: "So, what we saw in the last video was not a polyp, but an irritated part of the bowel?"
- C: Yeah, it was very low lying, it was really just a patch of irritant.
- C: We have a bigger piece now, so you can see the glands look tiny here.
- S: So on the last slide, about how big would it be on here?
- C: It would be about a piece like that. To be fair, it was probably what was underlying this area here.
- C: And then, it grew on to be something more.
- S: It wasn't this exact one, but it could've grown on to be something like this.
- C: Yes. When we have a colon resection, if there's a cancer, there's often a polyp...
- ...an area, a patch like we saw with hyperplasia.
- S: [The patch is] not necessarily where the cancer is, just [the cancer would be close]?
- C: Yeah, we find that if people have a colon cancer, they have a lot of pre-cancer regions.
- S: So, you can see that their bowel has been going through a lot of trauma.
- C: Some of its familial susceptibility, but a lot of it is that they are showing a propensity to do this...
- ...don't know if it's from environmental exposures or what.
- S: I see. So just to remind myself on what we're doing here, you cut out a piece of colon...
- ...because there was cancer there, and there might be a polyp in the same section
- that you cut out, and that 2nd slide where we saw the irritation might be right there.
- C: As a matter of fact, it's important you normally wouldn't see this slide in a patient,
- because almost all polyps, the colonoscopist is coming in, and they remove it through the colonoscope.
- S: Because they don't know if it's cancer or not.
- C: They'll remove it, but you wouldn't see the full wall. So right here, that's all the way through t
- wall and what you got here is muscle. So this really a full piece of the wall.
- C: So this is a larger piece, to show the polyp in its natural environment.
- C: So we're going to look at the polyp. First, way out here, the normal architecture
- C: So we said there are supposed to be tubes. Luckily, this one is cut right down the middle of the tubes
- C: so you can see how big the holes are.
- C: So, this is normal architecture there. If I go out a little bittle, you'll see an area here
- in which there is a bit of irritation. So, it's a thrown up [?] a bit like we saw before,
- but the real trouble is this thing sticking out. And we wonder, what is this thing sticking out.
- C: And so, for the medical students, we tell them to think like the pathologists,
- First need to look at the overall architecture: This is an abnormal architecture.
- We don't usually see a polyp sticking out.
- S: In 3D, would it look like a mushroom?
- C: Yeah. Actually, they tend to have a folding in the tops so they are more like cauliflower.
- S: Color?
- C: They don't have much color to them. The colonoscopist, when they look at them,
- can kinda tell if there's a chance of cancer because they begin having weird blood vessels.
- S: Just to be clear, they're not this purplish color.
- C: No, we have to stain these thin-sections or it would be colorless.
- C: So now, I am going to draw an area where I'm going to do a comparison. See this box here?
- C: So these are cells which are relatively normal. And these [on the top] are cells which are abnormal.
- C: A pathologist immediately say, "These look angry."
- S: They do! They do look angry! I would say that, too!
- C: What's angry about them: First of all, they are not committed to behaving.
- C: Proper behavior over here: nuclei belong at the bottom; things you're supposed to do for your job
- are at the top. So, when you look at these guys, you're like, "Where's your job?"
- C: And so, a few of them are making mucin, but these ones have nuclei of different sizes and shapes.
- C: They're just doing their own thing, not producing mucin, all they're doing is growing.
- C: Usually there's a playoff between, if you're committed to your specific job, we call it differentiation.
- C: So if you're committed to your differentiation, you tend not to have as much propensity to grow,
- and if you grow a lot, you tend not to do the differentiation.
- C: And so, this is largely that you have this chaos of nuclei, less commitment to the normal structures,
- and you're not producing as much.
- C: And so, what this is, is this is now called 'dysplasia.' ['Dys' is from Greek for 'mal'; malformation.]
- C: We're saying: We don't like their looks. These individual cells look dysplastic in their growth.
- C: So then, to tell whether it's cancer: Cancer means, in this organ, that you've grown across this line
- in the sand.
- S: So, literally, if you've crossed this boundary--cancer.
- C: Right.
- S: So, even if I'm in the polyp up here and I'm growing uncontrollably,
- and mutated and not killing itself [when it should; not responding to apoptotic signals]
- you still would not officially call it cancer?
- C: No, what happens is that there is a middle-term for a cancer that remains in its usual place:
- That's "carcinoma in situ."
- C: So, carcinoma in situ means that it's not an invasive cancer,
- so most people would not even call it a cancer.
- But it's just so wild looking up here, you know that it would [become "real cancer"]
- if given chance and time.
- S: What we're saying is that if there were carcinoma in situ out here, that it eventually would make
- its way.
- C: Right, it would continue to grow, because there is so little differentiation that you know it would
- continue to grow until [it became cancer.]
- C: With here, though, it's still dysplasia, where it's upsetting that it's growing so fast,
- but what's important about this, is that in hyperplasia, if you took away the stimulus or irritant,
- it would go back to normal--this would not [go back to normal.]
- S: If the irritant were removed in hyperplasia, it would go away in time.
- S: This dysplasia is here to stay.
- C: So the key word is "autonomous." So it will grow no matter what.
- It doesn't care about clues from neighboring cells, it doesn't need something driving it,
- so what you have then is if this is growing, and if it's growing all by itself, it's called a "neoplasia."
- S: So neoplasia means showing dysplasia?
- C: Dysplasia is when you look at these features, these cells aren't growing right.
- C: And then, overall, this lump is a "new growth," a neoplasia.
- We reserve the term in the medical field for meaning: It's growing on its own.
- S: How do we know it's new? How do we know it wasn't around for a year?
- C: I think it was. It probably came from this area here,
- and the thinking is that you probably had irritant here, hence hyperplasia,
- it would continue to grow--cells divide, cells divide too much,
- and then, [mutations occur (cancerous cells are rarely a result of only 1 mistake)],
- the cell says, "You know what? From now on, I'm not listening to any clues."
- S: And then, its descendants would be crazy, too?
- C: Right, they would have a real mean streak. And then they would grow from here.
- S: (I see that pattern in my own family!)
- C: So here, these are more normal glands, but even these--that's dysplasia.
- C: So these are growing without a good pattern of growth.
- And overall, this lump, is a neoplasia.
- S: So when we say "new," we mean, "newer than the other tissue"?
- C: We don't mean newer than the other so much as it's its own thing.
- C: New kid on the block.
- C: So this one right here is a polyp, it has features of dysplasia, but we see no cancer.
- S: How would you know? Oh, because it didn't cross the boundary line.
- C: There is a reason why the boundary is important, because if you look here,
- these are all the surface cells, down here, these are the vessels that go to the rest of the body.
- C: So these are blood vessels, these are called lymphatics,
- and what lymphatics are, they take the clear fluid [v. blood fluid]
- S: These right here, these are the lymphatics, the clear fluid.
- S: Fluid can go back and forth between the blood vessels and the lymph system?
- C: Yeah, usually what happens is: Blood comes in an artery like this,
- goes on down to these little vessels, and then a little bit of the clear parts of it,
- will kind of leak out.
- S: The blood cells are too big [to leak]?
- C: Yeah. So, some clear stuff comes out, and this is how it returns to the rest of your body,
- through these lymphatics.
- C: So you can see, you do not want neoplastic cells in here.
- S: Right, because once they are in there they can go to any part of the body.
- C: Go to a new place, and guess what? Set up shop, new kids on the block, they just do what they wanna.
- S: So that's called...I can't pronounce it...
- C: Metastasis. So, metastasis would be, if it gets into these things,
- it can get out of the colon and go anywhere.
- C: So this is one where it is not cancer, it has not invaded these areas where it can [metastasize.]
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