Hi datalou,
A microadenoma is a tumor that measures less than 10 mm in diameter.
Most microadenomas are prolactinomas, meaning they are small tumors
that secrete excess prolactin. Larger tumors are more aggressive, and
harder to treat and control.According to eMedicine, ?As with adenomas
in other endocrine glands, all these tumors probably derive from a
local mutation, with loss of function of the genes controlling cell
proliferation.?
A microadenoma prolactinoma may not present with any symptoms, if the
rise in prolactin is slight. Some symptoms in women are galactorrhea
(inappropriate lactation), amenorrhea (lack of menses or period), or
infertility. Men?s symptoms may include hypogonadism (testes do not
function properly), decreased libido (sex drive) or erectile
dysfunction.
http://www.emedicine.com/med/topic2973.htm
?A prolactinoma is a benign tumor of the pituitary gland that produces
a hormone called prolactin. It is the most common type of pituitary
tumor. Symptoms of prolactinoma are caused by too much prolactin in
the blood (hyperprolactinemia) or by pressure of the tumor on
surrounding tissues.?
Postmortem studies of the US population show that about 25% had small
prolactinomas. About 14 out of 100,000 people get significant health
affecting tumors.
Sometimes the source of elevated serum prolactin is caused by other
things, such as drugs, (including trifluoperazine (Stelazine) and
haloperidol (Haldol), metoclopramide (Reglan), and alpha methyldopa
and reserpine), hypothyroidism, breast stimulation, and other
pituitary tumors.
Increased serum prolactin can interfere with normal brain function-
specifically controlling the ovaries in females, and the testes in
males. Increases prolactin can cause a decrease in estrogen and
testosterone, which can increase chances of osteoporosis and blood
vessel damage, if not treated.
Massachusetts General Hospital
http://pituitary.mgh.harvard.edu/prolacti.htm
http://www.pituitary.org.uk/conference/2001/prolactinoma.htm
Causes
======
As posted by commenter, corwin02, the cause of prolactinomas is not
completely understood. According to The Pituitary Foundation,
prolactinomas occur when the cells that produce
prolactin,(lactotrophs), start dividing faster than normal. This may
be caused by a mutated gene in the lactotrophs. ?Although there is no
supporting evidence for head injuries triggering the condition, the
possibility cannot be ruled out entirely?
The Pituitary Foundation, University of Wales
http://www.pituitary.org.uk/conference/2001/prolactinoma.htm
Treatment
=========
The first step in treating a prolactinoma, is to decrease levels of
prolactin, while reducing the tumor in size. Should the tumor be very
large, sometimes the tumor may be only partially shrunken. The drug of
choice is usually bromocriptine, a dopamine agonist, causing a
decrease in prolactin production, and is effective in about 80% of
patients. Bromocriptine also slows the rate of tumor cell division and
growth of individual tumor cells.
Common side effects of bromocriptine include nausea, nasal stuffiness,
and dizziness associated with orthostatic hypotension (a drop in blood
pressure upon standing from a sitting or supine position).
In case a patient can not tolerate bromocriptine, or if the drug does
not perform well, surgery and/or radiation may be considered.
?Depending on the size of the tumor and how much of it is removed,
studies show that 20 to 50 percent will recur, usually within five
years?
According to eMedicine, ?For prolactin-secreting microadenomas,
surgical removal is followed by recurrence in about 50% of patients.
Therefore, medical therapy is preferred?
http://pituitary.mgh.harvard.edu/prolacti.htm
http://www.emedicine.com/med/topic1915.htm
Quinagolide, (Brand name ?Norprolac?) manufactured by Sandoz
Pharmaceuticals, is another relatively new drug which has been proved
effective in the UK. It too is a dopamine receptor agonist, but needs
to be taken just once a day, however it is much more expensive than
bromocriptine.
http://www.pituitary.org.uk/conference/2001/prolactinoma.htm
http://www.keele.ac.uk/depts/mm/MTRAC/ProductInfo/summaries/Q/QUINAGOLIDEs.html
http://www.gpnotebook.co.uk/simplepage.cfm?ID=-570032107
You can see a CT scan of a microadenoma prolactinoma at Rob?s Radiology
http://www.geocities.com/HotSprings/Villa/2545/microad.html
More CT views, and MRI
http://www.geocities.com/HotSprings/Villa/2545/macroad.html
You may be interested in reading this AOL Hometown list of other
prolactinoma sufferers.
http://members.aol.com/tomajestic/Page8.html
Additional Reading:
http://pituitary.mgh.harvard.edu/NCBV9I1.htm
http://jcem.endojournals.org/cgi/content/full/83/8/2777
I hope this answers your question! If any part of my answer is
unclear, please request an Answer Clarification, before rating. This
will enable me to assist you further, if possible.
Regards,
crabcakes
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