For over a decade, we have been offering support and information for
pheochromocytoma and related conditions. Our group is the original
support group, started in 1997 by several persons who had direct or
indirect experience with pheochromocytoma and related conditions. We
have a large and active support board where a great deal of practical
and up to date information can be found.
Pheochromocytomas are catecholamine producing
tumors of chromaffin cells, that can occur sporadically or as part of a
familial
syndrome. Although the majority are found in the adrenal glands,
pheochromocytoma
can basically be found wherever chromaffin tissue can be found.
Ninety-seven
percent have been found in the abdomen, 2% in the thorax and 1% in other
regions.
The tumor is named for its colorful reaction
in fixatives containing chromic acid salts. In modern day language,
these
tumors are often referred to as "pheos". Most pheos secrete a number of
hormones,
including norepinephrine, epinephrine, dopamine, vanylmandelic acid, and
metanephrines. Pheochromocytomas are usually benign (non-cancerous), but
can cause dangerously high blood pressure and other symptoms, including
pounding
headaches, heart palpitations, flushing of the face, nausea, and
vomiting.
Pheochromocytoma symptoms usually include paroxysms of extreme
hypertension,
accompanied by sweating, headache, and other autonomic disturbances,
probably
resulting from physical compression and/or ischemia of the "pheo".
Doctors
and patients often refer to these bouts as "episodes".
Pheochromocytomas can be found anywhere
in the body, though most occur in the adrenal medulla. Even a tiny
benign
pheochromocytoma can make a person very sick. Regardless of location and
appearance, the patients will usually report anxiety, headache,
palpitations,
panic attacks, sweating, and dizziness as some of the main symptoms.
Extra-adrenal paragangliomas (often called extra-adrenal
pheochromocytomas)
are closely related and less common tumors. These tumors originate in
the
ganglia of the sympathetic nervous system and are named based upon the
primary
anatomical site of origin.
It is estimated that approximately ten
to twenty-five percent of pheochromocytoma cases are genetic. There are a
number of these genetic types of conditions, including Multiple
Endocrine
Neoplasia Syndromes, Von Hippel-Lindau, Von Recklinghausen's
Neurofibromatosis,
Succinic Dehydrogenase Mutation. One of the MENS illnesses which is now
called
MEN2A was once called MEA, or Multiple Endocrine Adenoma Syndrome. More
thorough
information about all of these conditions can be found in our
information
links and support message boards shown on the left sidebar.
The Pressor definition of
pheochromocytoma:
"Pheochromocytomas are neuroendocrine tumors derived from
catecholamine-producing
chromaffin cells of the adrenal medulla, whereas extra-adrenal
paragangliomas
arise from chromaffin cells of the extra-adrenal paraganglia (a
pheochromocytoma
is an intra-adrenal paraganglioma). It was agreed to adopt the 2004 WHO
classification of endocrine tumors where pheochromocytomas are defined
as
tumors arising from catecholamine-producing chromaffin cells in the
adrenal
medulla. According to this classification, closely related tumors of
extra-adrenal sympathetic and parasympathetic paraganglia are classified
as extra-adrenal paragangliomas. The recommendation to adopt this
simplified
definition was based on the need for international standardization.
However,
as long as the istopathological and clinical entities are well-defined
and
accounted for, for purposes of genetic testing the two types of tumors
should
often be considered together because they often have a common genetic
basis."
The Endotext version/discussion of the
definition of pheochromocytoma in more thorough details:
"Pheochromocytomas are chromaffin cell tumors that produce, store,
metabolize,
and secrete catecholamines. The metabolism of catecholamines is a more
consistent
process than that of catecholamine secretion. The 2004 World Health
Organization
classification of endocrine tumors defines pheochromocytoma as a tumor
arising
from catecholamine-producing chromaffin cells in the adrenal medulla —
an intra-adrenal paraganglioma. Closely related tumors of extra-adrenal
paraganglia are classified as extra-adrenal paragangliomas. While these
definitions serve to distinguish the two types of tumor based on
location,
this does not take into account differences in functional
characteristics
related to other differences in cellular origin. More specifically,
while
extra-adrenal paragangliomas derived from sympathetic nervous
system-associated
chromaffin tissue almost always produce catecholamines and often lead to
hypertension, those derived from parasympathetic tissue (mainly head and
neck paragangliomas) produce significant amounts of catecholamines in
only
less than 5% and usually do not cause hypertension. It therefore seems
likely
that pheochromocytomas will be continued to be defined as
catecholamine-producing
tumors of intra- and extra-adrenal chromaffin cells, with those derived
from
from the latter types of chromaffin cells classified as extra-adrenal
pheochromocytomas. Pheochromocytomas typically occur in about 85% of
cases
from adrenal medullary chromaffin tissue and in about 15% of cases from
extra-adrenal chromaffin tissues. Extra-adrenal pheochromocytomas in the
abdomen most commonly arise from a collection of chromaffin tissue
around
the origin of the inferior mesenteric artery (the organ of Zuckerkandl)
or
aortic bifurcation. Most pheochromocytomas represent sporadic tumors and
about 20-30% of pheochromocytomas are familial. Sporadic
pheochromocytomas
are usually unicentric and unilateral while familial pheochromocytomas
are
often multicentric and bilateral. Both adrenal and extra-adrenal
paragangliomas
display similar histopathological characteristics. Unusual sites in the
abdomen
and pelvis include kidney, urethra, prostate, spermatic cord, genital
tract,
and liver. About 4-10% of patients with pheochromocytoma present with
adrenal
incidentaloma, whereas approximately 5% are diagnosed at surgery.
Although
metastases may be rare for adrenal (about 10%) and familial (less than
5%)
pheochromocytomas, the prevalence is up to 36-50% for extra-adrenal
abdominal
pheochromocytomas. Finally, up to 10% of intra-adrenal pheochromocytomas
show local recurrence. Pheochromocytomas occur in about 0.05% to 0.1% of
patients with sustained hypertension. However, this probably accounts
for
only 50% of persons harboring pheochromocytoma, when it is considered
that
about half the patients with pheochromocytoma have only paroxysmal
hypertension
or are normotensive. Also, it must also be considered that the
prevalence
of sustained hypertension in the adult population of Western countries
is
between 15% to 20%. Thus, in Western countries the prevalence of
pheochromocytoma
can be estimated to lie between 1:6,500 to 1:2,500 with an annual
incidence
in the United States of 500 to 1,100 cases per year. Despite this low
incidence,
pheochromocytoma must always be considered since if it is identified the
condition can be cured in about 90% cases, whereas left untreated the
tumor
is likely to be fatal due catecholamine-induced malignant hypertension,
heart
failure, myocardial infarction, stroke, ventricular arrhythmias, or
metastatic
disease."
Sources:
Endotext
http://www.endotext.org/adrenal/adrenal34/adrenalframe34.htm
Pressor Organization
http://www.pressor.org/ips2005/details.htm#8
Wikipedia
http://en.wikipedia.org/wiki/Pheochromocytoma
Stanford University School of Medicine
http://cancer.stanford.edu/endocrine/adrenal/
National Cancer
Institute
http://www.cancer.gov/cancertopics/types/pheochromocytoma
Endojournals Organization
http://edrv.endojournals.org/cgi/reprint/15/3/356.pdf
