Let’s get into pathology.
Inside the medulla, you have a benign tumour.
This benign tumour episodically might then
be releasing epinephrine.
When you increase your epinephrine, what happens?
You’re going to have increased blood pressure
for reasons we’ve talked about.
Beta-1 receptor activity increasing your heart
contractions, increases systolic blood pressure.
Uncommon neoplasm, but my goodness, do you
want to know this for your boards.
These are your medulla chromaffin cells.
Whenever you have... now, for board purposes
know this… clinically speaking, in medicine,
the term or the concept of paraganglioma is
actually quite complicated.
I will give you the-the absolute minimum or
what’s necessary for you to get the questions
right here, but if you find a-a epinephrine
producing tumour outside the adrenal medulla,
then you call this a paraganglioma.
When from extra adrenal chromaffin cells,
the operative word extra, this is then referred
to as being paraganglioma.
So, where would this be located if it’s
not in the adrenal medulla?
Bifurcations, of what?
Bifurcations of blood vessels such as the
carotids up here, internal/external bifurcation
of the carotid artery and then the iliacs.
Pheochromocytoma, reaction with dichromate
fixation helps you… you want to know about
a particular staining mechanism.
Tumours of the adrenal medulla generally may
be sporadic associated with inherited… we’ll
talk about this in great detail.
Including neurofibromatosis type I, we’ll
talk more about neurofibromatosis type I in
neuropathology in which then gives rise to
a particular type of brain issue called neurofibroma
all associated with and you must know of von
Von Hippel-Lindau disease is extremely important
for you and I in pathology because of its
molecular mechanisms including something called
hypoxia-inducible factor 1-alpha and the fact
that it works on your VEGF.
If you’re not familiar with any of that,
this would probably be a good time to go back
and take a look at the chapter neoplasia that
we are… that we have covered and in which
I’ll walk you through in great detail about
increasing-increasing your effect and influence
of VEGF in a cancer with Von Hippel-Lindau
in which you have bilateral renal sarco…
Succinate dehydrogenase submit gene mutation
and MEN 2 syndromes.
Why did I emphasise “es”?
Because it’s part of both MEN2A and 2B.
What is pheochromocytoma?
So, earlier when we began this section, I
told you the medulla and the pathology of
it is not to be underestimated because of
its incredible links to other subjects - biochemistry,
physiology, pathology and other pathologies
and its associations that we’ve already
had discussions, but you must bring all of
it together now.
Epinephrine/metanephrine predominates suggests
MEN2A and 2B; bilateral tumours, familial
history, young age or paragangliomas such
as genetic syndromes.
Think about it as being a pheochromocytoma…
Where is it located?
Bifurcations maybe the iliacs and maybe the
Correctable, meaning to say that the hypertension
here is not constitutive, what that means
is that the hypertension is not going to be
This is pheochromocytoma, your focus here
Presentation and Diagnosis: triad… headaches,
sweating, palpitations during the episodes.
Anxiety, nervousness to the point where feels
like impending death by the patient; severe
tremors, pain in the lower chest, upper abdomen
all due to increased sympathetic activity.
Nausea, weight loss, heat intolerance, incredibly
high levels of epi, epi, epi, epi… increasing
About half will have what’s known as paroxysmal
hypertension, meaning to say that it’s refractory,
it will not pay attention, or should I say,
it will not respond to conventional medication.
Hence, you get into interesting drugs such
Most others appear to have essential hypertension.
Presentation and diagnosis is important for
you to pay attention to.
There is no sign that is a best test, do not
look for buzz words; most common however will
be the fact that you’re going to look for
your metanephrines 24 hours.
You’ve heard of vanillylmandelic acid…
plasma free metanephrines.
The metabolites are more sensitive than parent
catecholamines… the metabolites of epi.
Always confirm a biochemical test.
However, before doing any imaging study, and
I have emphasized that throughout this entire
lecture series, always look for biochemical
test before doing imaging.
Next step of management with imaging MRI’s
Once you do an MRI of the abdominal region,
you will then notice that there is a tumour
in the adrenal gland specifically in the medulla,
but you correlate this please first with diagnosis.
Meaning to say that your labs that were showing
the metanephrines and the vanillylmandelic
acid in the urine.
If the MRI is unrevealing then you might be
thinking about using radioactive diagnosis
and this brings us to MIBG scintigraphy which
There is something called the rule of 10’s
or the rule of 10 percent of pheochromocytoma,
it is important that you know these.
Majority of your pheochromocytomas are benign,
10 percent are.
Majority of your pheochormocytomas are unilateral,
10 percent are bilateral.
Majority of your pheochormocytomas are in
your adrenal medulla, 10 percent might be
extra adrenal… welcome to paraganglioma.
Majority of your pheochormocytomas are in
adults, 10 percent might be in children.
Majority of them are sporadic, 10 percent
might be familial… put familial and paraganglioma
10 percent are associated with MEN2A and or
2B; 10 percent may recur…
10 percent rules of pheochromocytoma.
Treatment consists of surgically excision
of the tumour, remove the darn tumour.
Since surgery can precipitate catecholamine
release from the tumour, patients are prepared
with your phenoxybenzamine so that you would
Control, control, control your blood pressure.
That is what’s most important.
I don’t care what kind of surgery that you’re
doing, you want to make sure that your patient
is not in a state of bleeding and definitely
controlling his or her blood pressure, right?
Prior to operation, beta blocker prior to
alpha blocker should be avoided as it may
lead to severe hypertension due to unopposed
alpha adrenergic activity.
Patients with large pheochromocytoma increase
risk of malignancy, remember 10 percent could
be malignant or paraganglioma… once again
These individuals should then undergo the
MIBG scintigraphy… metaiodobenzylguanidine.
The sporadic is the majority of our type,
that is where our focus here is, 90 percent,
ages 40-60; 10 percent will…
10 percent bilateral, 10 percent malignant.
Hereditary form important, important associations.
Childhood, males, bilateral, von Hippel-Lindau,
what does that mean to you?
Renal carcinoma… automatically renal carcinoma.
What if your patient is ataxic as a gait?
Good, hemangioblastoma in the cerebellum.
What if there’s visual issues?
Hemangioblastoma in the retina.
Sturge-Weber… child… half the face is
Called as port wine stain, could have… that
child might have neo onset seizures because
of space occupying lesions due to what’s
known as leptomeningeal arteries.
You can have neuroblastomas that are associated
and we will get into 2A and 2B in just a little