Our non-small cell lung cancer include adenocarcinoma.
Let’s take a look.
Adenocarcinoma, know everything about this
lung cancer. It is the most common type of
lung cancer. Period. Okay. The last time we
even discussed bronchogenic lung cancer, do
you remember a particular pneumoconiosis that
was associated with the development of bronchogenic
carcinoma decades down the road? Good, maybe
the patient was a roofer, a plumber, right?
Maybe the patient was working in a naval shipyard.
That was asbestosis. Good. And that asbestos
is going to then affect what part of the lung?
The basal or the upper lobe? It was really
the only one of the four pneumoconiosis that
was affecting the basal. So, that was our
discussion back then. We’ll take a look
You tell me, first, a primary lung cancer,
how many nodules? Good, one. This nodule,
if it was small cell, was located where? By
the mediastinum. How do you describe this
clinically? Central. Chest X-ray for adenocarcinoma,
you pay attention to peripherally located
one nodule. By periphery I do not mean
the pleura. Adenocarcinoma is not a cancer
of the pleura. You give me a diagnosis where
cancer of the pleura has taken place. It’s
mesothelioma, okay? Not here. So, by peripheral
let's just say away from the mediastinum,
peripherally located. How many nodules? One.
Why not two or three? That’s metastasis.
What’s the number 1 place for metastasis?
Can’t say number 1, but give me couple
of common metastasis of a primary cancer
to the lung. Good, liver. Give me another
one. The lung is right around, the breast.
Okay, keep those in mind.
Characteristics of adenoma. We’ll walk through
each point here. Most common primary lung
cancer, point 1. Point 2, the activation
mutations. Well in neoplasia we’ve talked
about plenty of these. The one that’s
most famous of them all, RAS.
Remember RAS? Associated with what? GTPase.
Remember that? Bring it in here. Here RAS becomes
important and you find that in many
cancers. With EGFR (epidermal
growth factor receptor). Last time we’ve
talked about that was with breast cancer,
right? Epidermal growth factor receptor. And
then you have an important one. ALK. This
is anaplastic lymphoma kinase. This is going
to be little bit more specific for adenocarcinoma.
Luckily and conveniently, both begin with
the letter A.
Next, when you have bronchogenic carcinoma,
we take a look at the digits. And looks like
the nail is expanded. This is called hypertrophic
osteoarthropathy. We’re not exactly sure
what causes this, but the bone underneath
your nail, osteo, undergoes hypertrophic changes.
Literally it pushes the nail upwards. Looks
like clubbing, but you don’t call it clubbing,
because clubbing would be what? Clubbing would
be part of chronic hypoxia, do you remember that?
So here we have hypertrophic osteoarthropathy
as more or less your paraneoplastic issue
that you’d find with bronchogenic in a whole,
Now, the subtypes are important for us. We
have in-situ. What’s in-situ mean to you?
It means that membrane is intact. Just because
the membrane is intact, does it mean that
you’re not malignant? My question once again,
just because the membrane is intact, in-situ,
does it mean that you’re not malignant?
No. You could be in-situ and still be malignant.
Welcome to the in-situs of the breast. Lobular
carcinoma in-situ, right? The breast,
the ductal carcinoma in-situ.
Luckily the membrane has not been ruptured.
So, the adenocarcinoma in-situ is known as
the bronchoalveolar subtype. It will show
hazy infiltrates similar to consolidation.
Be careful. Consolidation, well, you usually
think about pneumonia, but there you would
have fever and such. In chest X-ray maintains better
prognosis. Characteristics of adenocarcinoma:
be familiar with the in-situ subtype known
Let's take a look at histology here. Now,
before I move on, you tell me what adenoma
means. For example, stomach cancer – gastric
adenocarcinoma. Per-rectal cancer – adenocarcinoma.
Prostate cancer – adenocarcinoma. Breast
cancer – adenocarcinoma. Adenoma means
what? Those are all glandular structures,
aren’t they? So, glandular, tall, columnar.
Adenoma. So that’s non-specific, that just
means glandular, you knew that already.
Now, pattern on histology, are they going
to now stain? Once again, you have something
that’s a glandular, it will be mucin positive.
Okay? Mucin positive. Do you have any of that
paraneoplastic craziness that we saw with
small cell? We saw what? ADH, ACTH and stuff.
No, not here. So, you wouldn’t expect to
find the Kulchitsky cells and the chromogranin
A and neuron-specific enolase. The bronchoalveolar
subtype grows along the alveolar septa. What’s
bronchoalveolar? See what’s bold in here,
go back to characteristics. It means in-situ.
So, subtype of this grows along the alveolar septa
with apparent thickening of the alveolar wall.
Rupture? No, this is not invasive, it's
in-situ. Spend time, make sure you at
least know this much of adenocarcinoma before
you then move on to any other lung cancer.