The way to approach thymic pathology
in this section would be, well,
is the thymus present?
So maybe perhaps thymic hypoplasia
or is there too much
Let’s take a look.
First, we’ll take a look
at a congenital disorder
that you should be quite familiar with
in which, literally, the
thymus does not form.
This obviously is going to bring
you to a topic of DiGeorge.
So DiGeorge syndrome as you see in
the picture here is showing you
that the third and fourth pharyngeal
pouches, which are normally responsible for
developing the superior
and inferior parathyroids
and then also the third
not only does it give rise to
your inferior parathyroid,
but it will also give
rise to your thymus.
And the DiGeorge syndrome, as you
know, chromosome 22, long arm 11,
that you don’t have this.
Abnormal development of third
and fourth pharyngeal pouches,
loss of the thymus, now how’s
your patient presenting?
Well, you know about
Recurrent infection has a long list
of differentials including DiGeorge,
including your Chédiak-Higashi,
the list goes on and on and on.
And those become
important in immunology.
Here, if the thymus is not present,
then your patient is most likely
susceptible more so to viral infections,
but you know the peculiar symptom
that you’re going to find here
that you would in other conditions,
that have recurrent infection will
be the fact that if for example,
if you placed pressure or if you
snapped on your facial nerve,
that you would have Chvostek sign, or
in other words, you're eliciting tetany
or perhaps a cuff around the arm
and therefore resulting
in carpopedal spasms or
oral mucosa type of
All of these put together with DiGeorge
Syndrome and just to be complete,
that chromosome 22q11, you’ve
heard of velocardiofacial issues.
That becomes important
Spend a little bit of time
with that chromosome 22,
what may then happen
if that gets deleted?
Not only could it be DiGeorge, but another
condition that’s important called
Here, our topic is hyperplasia,
thymic, follicular hyperplasia,
why does this occur?
Occurs in chronic inflammation
in immunologic states.
Remember what the thymus is
responsible for in a child.
Obviously, as an adult, our
thymus gets involuted, apoptosis.
We don’t have a
We shouldn’t and
At some point, I’ll walk you through another
set of diagnosis called thymomas, okay?
But here, it’s the thymic hyperplasia.
Remember that thymus is responsible
for proper education of your T-cells.
So T-cells are being born
out of your bone marrow,
they then come to your thymus,
for proper education.
In other words, to make sure that
you get rid of the self T-cells.
by myasthenia gravis.
We’ll talk about this
in greater detail.
Oftentimes, you’ll find thymus in
which it undergoes hyperplasia,
which may then be
called a thymoma.
I’m setting you up as to what’s to come.