Welcome to neoplasia. What does that mean to you? Proliferation of cells.
Means that the cell is going to remain witin the cell cycle for a long period of time.
And depending as to it's behaviour may then go on to be more benign in nature or malignant
By the time we are done with this particular section, you'll have then become an expert in
basics of neoplasia.
Neoplasia. New growth, not reversible. It is a key. Even with benign, remember.
If a cell undergoes increased mitotic rate at some point in time within that cell cycle,
meaning to say that you are in the M phase, very difficult to reverse that.
Dysplasia, very important topic. For example, let's say that you have a organ, that has
undergone hyperplasia. At any point of time with hyperplasia, which means increased number, right?
And one would think with hyperplasia that there might not be a tendency of going on to neoplasia.
That is incorrect. For example, if there is endometrial hyperplasia that might be taking place in a patient
who is above the age of 50, a female. Meaning to say post-menopausal, and you start bleeding.
You see bleeding coming out of cervical os. Hmm, kind of worried now aren't you?
That there is possibility of endometrial hyperplasia and then concerning of endometrial cancer.
But it's not like hyperplasia went in to cancer, right?
It has to go through a period of dysplasia.
So, put things into perspective. Or, for example, you have heard of HPV.
And you have heard of high risk strains 16, 18, 31, 33.
And you should be thinking about the cervix. And with the cervix, in the developing country in the world,
cervical cancer is a pretty big deal. But before it went into cervical cancer, what kind of changes did
the cell of the cervix undergo? CIN I, CIN II, CIN III. Cervical intraepithelial neoplasia,
we have to call this dysplasia. So dysplasia is not neoplasia as of yet but my goodness is it close.
And you, as a clinician, you hear the term dysplasia, you're absolutely worried about your patient going on to cancer.
It's disordered growth which is reversible but unfortunately may result in neoplasia.
As a rule of thumb, as far as you are concerned, even with the most severe or serious type of dysplasia
in cervix, let's say CIN III. With that high grade type of dysplasia, it still would take approximately
a decade for that dysplasia to go on to cancer. Keep that in mind.
Dysplasia is a very important topic for us. What is a tumor?
A tumor is swelling. In basics, with tumor hemodynamics we talked about histamine causing, tumor.
How was that possible? Histamine caused vasodilation therefore bringing about enlargement.
In this case, with basic neoplasia we are dealing with increased proliferation of cells, therefore
we have a tumor. And the behaviour of that tumor can be either benign or malignant.
We will be spending time with that. Now, before we move on though, the other point of
demarcation here would be, malignant and metastasis. Just because you have a cancer
or a neoplasia that is malignant, you are one step closer to perhaps metastasis but malignant,
does'nt always have to go into metastasis. It's one step closer. So you are definitely worried about
that increase proliferation and therefore causing rupture or penetration through the basement membrane.
We will talk further about this. And then we have actual cancer.
Cancer would be malignant neoplasia. For example, if you had renal cell carcinoma or colorectal cancer
so on and so forth. And then with this type of cancer you are worried about the membrane rupturing and
therefore entering, spread. In other words, you have now gone on to the highway.
What I mean by that is, you have ruptured the membrane, you have entered the highway
and that highway means to say either the lymphatic or perhaps hematogeneous spread.
And once that happens, then my goodness you are going to have spread of that cancer,
well step by step by step. Regional lymph nodes. From the regional lymph nodes it might
then go on to further lymph nodes and before you know it there is widespread metastasis.
How important is metastasis? If you remember, often times the most common cancer within an
organ is not primary. It will be metastasis from a primary.