Master the board step 3

Endocrinology
Prolactinoma
Prolactinoma is the most common pituitary tumor. It presents differently in
men and women:
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Men
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Presents with impotence, decreased libido, and occasionally gynecomastia.
Presents late. No man rushes to the doctor in a panic to yell, “I
can’t get an erection and my breasts are big, too!”
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Men are more likely to have the signs of mass effect of a tumor, such as
headache and visual disturbance.
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Women
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Amenorrhea and galactorrhea in the absence of pregnancy has women
presenting early.
Basic Science Correlate
Prolactin inhibits GNRH. If there is no GNRH, the body cannot release LH
and FSH.
Prolactinoma should only be investigated under the following conditions:
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Pregnancy has been excluded.
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Drugs such as metoclopramide, phenothiazines, or tricyclic antidepressants
have been excluded as the cause of the high prolactin level.
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Prolactin level is very high (> 200).
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Other causes of hyperprolactinemia have been excluded:
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Hypothyroidism: High thyrotropin-releasing hormone level stimulates
prolactin
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Nipple stimulation, chest wall irritation
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Stress, exercise
Diagnostic Testing
The most accurate diagnostic test is an MRI of the brain.
Treatment
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Best initial therapy: Dopamine agonist agents, such as bromocriptine or
cabergoline. Most prolactinomas respond to dopamine agonists.
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Surgical removal is performed for the small number of patients in whom
medical therapy does not work.
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