Really like this section on cancerous colon tissue. Would like to learn more? and more about metasticide .
When a dysplastic polyp spreads towards the muscle with the lymph vessels and blood vessels, this is cancer. There is lots of chaotic growth where nuclei are enlarged (more DNA replication), and these cells do not carry out their function. Grading is based on the number of cancer cells and how chaotic the growth is. Stages are based on the size of the cancerous region, if it has crossed the barriers and is near lymph nodes and if it has metastasised. There is also a wbc immune response in the area- many therapies are based on increasing this.
What is cancerous colon tissue?
An example of colon cancer. A view of the lumen which is the inside of the organ, and also the peritoneal cavity, which allows the process of peristalsis, which is the movement of the bowel. A pollup is formed, followed by Dysplasia, which changes the shape of the cells structure. This starts to divide uncontrollably among the normal cells, and grows all the way through down to the muscle. Surgical cure is usually the best cure for this kind of cancer (colon). Defines Mestastasis as the point when the cancer cells leave the original region and enter a tiny blood vessel. Discusses the grade and the different stages of cancer. Shows us the lymphocites which are the immune cells (plasmacells) that produce antibodies.
lumen is the is the inside of the of the intestine .prenuptial cavity is where all bowel movement is moving around . paresis is the muscle that pushes this along.
S: This is Sal again, and this is 4th in a series we're doing here at Stanford Med School w/Dr. Connolly.
Dr: This is the 4th of the slides, and this would now be the reason why this section of colon was removed.
This is cancer. So, just to orient. We're going to go to drawing.
Like you said before, this is the lumen, the inside. Out here is the rest of your belly.
S: Is there a word for your abdominal [insides]?
Dr: Peritoneal. So the peritoneal cavity is where all the bowel loops are just moving around.
What we have here is an important part, this is the muscle that allows peristalsis.
S: The undulating motion to push stuff.
Dr: Yes. It will milk it along. So the muscle is all fine there, that's how thick it's supposed to be,
and it's all fine here...
S: What scale is this? How thick is that muscle?
Dr: Our tiny little red blood cells are those tiny dots there, and so we're talking thickness here of
about a few millimeters.
S: So that muscle is a few millimeters.
Dr: Right. So remember that guy was about 6mm? That's about 6mm.
Dr: That's actually strong, a very strong muscle, you can kinda see it go up here,
it comes around here, but it looks like it's trouble along this area.
S: And this stuff was probably once a polyp and it just turned into this massive polyp?
Dr: Yes. So, we have the normal here, for the lining, this is where it's going dysplastic.
There's where it's going dysplastic.
And so now what happens is you got these edges of dysplasia..
S: When people in the medical field say "plastic," they word means...tissue?
Dr: Plastic in general, like plastic surgery, or the plastics in material science,
means moldable. It also means you can grow, you can change shape.
S: So when you call something plastic, it's moldable tissue?
Dr: It's the shape changes. So the shape changes were wrong.
Actually, dysplasia can refer to a cell, tissue, an organ, or an entire limb.
It just means that it grew wrong, it molded wrong.
So now, this is where we have the cell dysplasia,
this is all the bad stuff. It basically started somewhere up there and started invading.
S: Just one cell up there started dividing uncontrollably.
Dr: Right. It could have started from one cell being very bad,
it often starts though from one of these, meaning maybe a cell went bad right around there,
Now it's really starting to grow.
S: When you say grow, not the one cell but all of its descendants?
Dr: Its descendants. Millions and billions are now growing downward to now, in this case,
grow all the way through. And so you can see the scale is it not only grew a little bit,
it went right through the muscle.
S: The body does have some things to fight this off? But it was unsuccessful?
Dr: Right. There are certain conditions where if you decrease the immune functions
you'll get cancer. It's still argued if when the immune system decreases you get a virus,
and a virus causes the cancer, or whether the immune system is [actively watching out for cancer].
S: The whole notion of viruses is fascinating, because a lot of our ancient DNA is from viruses...
Dr: Yeah. There are some categories, where viruses can get into your DNA and really mess up your DNA,
and integrate into it, but viruses can also lead to irritation, with more cell growth and [likelihood
for DNA copy errors].
So now we're back where we're looking at the cancer that probably started around here,
and is growing, including spreading all the normal tissue around it.
Now we're going to look at the cells.
First, look at the edges of this. We find normal, though not perfectly normal.
You can see it's a little bit dividing and a little bit irritated. This is irritated along the edge.
Dr: Exactly! What we have when we go deeper, this is all coming out, growing in all directions,
this is where you can see cancer next to the normal.
We talked before about dysplasia, but this right here is really bad.
These are the normal ones, they're doing their job. They're making mucin, nuclei at the bottom,
What is this guy doing? It's just chaos. Before we talked about carcinoma in situ,
a cancer in a spot--if you saw cells this bad, you'd say, do not let them go far.
Because they will have a tendency to invade. They're crazy. So this right here is a bunch of the cells,
this is a bunch of the cells, they're these guys here.
You can see they're really haphazard in how they're growing,
they're not doing their job...
S: If we had a polyp that had this stuff that hadn't crossed that boundary line yet,
we'd still say, "We got to take this out."
...although I guess we already took it out.
Dr: Cancer of the colon is one of the ones where surgical cures still applies.
Cut it out, and you are probably in pretty good shape.
So if it looked like this only at the tip of the polyp, we'd probably got it out,
But you'd say to yourself, "We better watch this person."
S: If the whole polyp looked like that, you'd cut out a bigger section?
Dr: Yes, if it's going down into the neck, or going a little further,
or if you had cut it across the margin, then watch out.
But here's the problem: Remember how I said up here it's not a big deal?
But once you get near the veins and arteries?
These guys are running amuck, near the veins and arteries,
S: You can see these cells have split off, and infiltrating...
Dr: That's one little nest of cells,
that one is probably a cancer cell just dying to get into that little vein.
S: So this is metastasis?
Dr: This is where it would come from. So these guys are the bad actors,
growing next to these very fragile blood vessels, so that guy is knocking on the door,
wants to get in here--that's a venule, a little vein, that's the road out.
S: It looks like a circle here because it's a 2D cross-section of it,
but you can imagine it popping in and out of our screen.
Dr: Yes. So this guy might pop in and out of screen, connect to this one...
S: And it officially metastasized once it's found a beachhead someplace else?
Dr: Right. It's considered a metastasis if the cell got into the vessel and left the region,
This is looking like you really are worrying that this could metastasize.
What's interesting is when you're looking at something like this, there's something called
pre-cancer grade, and what grade is is what we've been talking about--
how bad does that look? And so the grade is, "Wow, that looks nasty."
S: Is nasty a technical term?
Dr: Actually we use it quite a bit. When we talk about nastiness, it's a lack of behavour,
if you can get a cell where the nucleus gets that big, or sometimes that big,
there's chaos. And there's chaos not just in the nuclear size, but how it behaves.
S: The nuclear size indicates that the cell is devoting cell replication?
Dr: Yes. But it also means to me--normally things in the cell are very orderly,
you do not divide your DNA until these things--now it's just left and right.
This would be a high-grade tumor, and stage is the other main thing.
Stage means where is it in the body.
So in this case, if these nasty cells were only at the very top, it would be a lower stage than
these which have come all the way down here.
S: In situ carcinoma, what is the stage?
Dr: Stage 0. It's basically nowhere. If you just begin to crossover, it's stage 1;
and then there's depth for some stages, and then there's always "did it go to other parts of your body?"
And that's the very highest stage
S: And this is true of all cancer--when someone speaks of breast cancer, I've heard of stage 0-4,
It isn't just the size--if the cancerous tissue is big, but in a safe place, still be stage 1 or 2?
Dr: It is. The whole world has agreed to the same kind of staging, and that staging is what we're calling TNM.
T has to do with how big it is, and how much it's crossed any barriers,
N has to do with if they are in lymph nodes. The lymph nodes are nearby structures where the lymph goes.
M has to do with metastasis.
Staging has to do with all three.
S: Metastases always has to happen through the circulatory system?
Through the blood vessels, or does it also happen through the lymph network?
Dr: It's something where going through the lymph nodes is one of the first steps for something like this,
but getting to the liver or the lung, it's got to get into the blood vessels.
The lymphatic in your colon connects to a local lymph node,
but does not connect through lymph only to the (...? be quieter, Sal!)
So it must have gone through the blood somewhere.
So that's the way it looks here. And the final thing when looking at this cancer is
if we go over here, this is the greatest depth of invasion.
You had asked me about the body's immune function.
Well, if you look here, you see how it's kind of loose?
There is all these little immune cells?
S: What's the immune cells?
Dr: These guys here. These little round guys? These are lymphocytes.
S: How can you tell the difference between the lymphocytes and the cancer cells?
Dr: Because I'm a pathologist...
They're these little round ones. Right here is a classic cell, which is called a plasma cell
in which there is a nucleus here, and all the rest is making antibodies
S: You're not circling that area are you?
Dr: No, I'm just drawing. So this guy is this one. So I'm zooming in on him.
Dr: That's a plasma cell, that's making antibodies probably against the tumor.
That's the immune response in that spot.
S: How do you know...that looks very similar to the cancer cells?
Dr: This one is a little hard to tell. If you had a real microscope, you'd turn up the light,
this would have a very specific look to the nucleus,
and these guys over here have little pink granules in them,
which is a type of immune cell.
S: Which ones are cancerous here?
Dr: These are all inflammation. The nearest cancer cells are these guys up here.
S: On this view it becomes obvious, they look different.
Dr: When you come out here, there's the cancer,
there's the body's reaction to the cancer.
There are therapies based on trying to get more of this immune response.
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