Another example of paraneoplastic
syndrome is amyloidosis.
The deposition of amyloid proteins as a result
of the elaboration of abnormal immunoglobulins,
say in the setting of a
plasmacytoma, or multiple myeloma.
What's going on here?
So here's a marrow of a patient who has not
a plasmacytoma, but has multiple myeloma.
So an increased number of
abnormal, malignant plasma cells.
So these are the terminally differentiated
cells, and they're cranking out a lot
of a particular kind of antibody.
Too much of that antibody, and especially
too much of the light chain of that antibody
will result in the formation of amyloid deposition,
extracellular deposition of amyloid fibrils.
Now, amyloid can be any of a variety of proteins.
And when we will, together talk about
cardiac pathology at some point,
I will talk about transthyretin-induced
amyloidosis in the heart.
In this case, it's the light
chains of the immunoglobulins
being synthesized by the abnormal
plasma cells and that is depositing
in the extracellular matrix so it's outside of cells.
Right here, we're looking at the left
atrium, and the left atrium has kind of a,
almost a candle wax dripping
appearance when we see it up close.
This is due to that profound deposition
of that abnormal light chain protein,
and it's now forming into fibrils
that we recognize as amyloid.
What does that look like?
Well, on a Congo red stain without putting
polarized light on it, it looks like this,
the individual cardiac myocytes are the
lighter pinker cells kind of throughout
and the more salmon-pink colored material
around them represents the deposition
in the extracellular space of amyloid protein.
This is the classic stain that we look for amyloid.
And when the appearance here
for me is characteristic,
but really what we're looking for,
is we put polarized light on it,
and we're looking for apple green birefringence.
So all the little green specks that you
see in there represent amyloid deposition.
And in fact, on the boards when they ask, what's
the diagnostic stain for amyloid deposition?
You're going to see a Congo red stain
and it's got apple green birefringence
when I shine polarized light on it.
Finally, let's talk about hypertensive crisis.
So in a pheochromocytoma, again,
potentially a benign tumor.
A pheochromocytoma's only 10%
are malignant, 90% are not,
but they will make catecholamines.
They will make epinephrine and that
can cause a hypertensive crisis.
So what's going on here?
This is an adrenal, on the left
hand side, it's a pheochromocytoma
In the middle, identified by the green circle,
and in this particular case, it's a benign tumor.
It does not have any malignant potential.
At higher magnification, we can
see what the cells look like.
They have rather large nucleus,
they are a little bit pleomorphic.
They have prominent nucleoli, open chromatin
pattern,and they have a very granular cytoplasm.
Well that granular cytoplasm is happily
making lots and lots and lots of epinephrine.
Now in this pheochromocytoma, in that adrenal per
se, there's not going to be much effect of the cancer
but the release of epinephrine from these
cells in this benign pheochromocytoma
will cause bouts of elevated blood pressure.
And in fact, you can have a
hemorrhagic stroke as a result of that.
You can raise the blood pressure into the 200
to 250 almost 300 millimeters of mercury level
and that will rupture blood vessels and
here we have just a hemorrhagic stroke
that is due to a hypertensive crisis emergency
and the patient died as a result of the hemorrhage
due to the pheochromocytoma.
And with that we are at a concluding point but
we're going to come back and talk about the way,
other ways that tumors interact with their host.