Forbes-Albright syndrome: A rare condition where a hormone secreting pituitary or hypothalamic tumor causes galactorrhea and amenorrhea.
Increased prolactin secretion Enlarged pituitary gland Galactorrhea Absence of menstruation Lack of ovulation
Galactorrhea usually develops in a person with increased prolactin secretion from the anterior pituitary gland, with possible abnormal patterns of secretion of growth, thyroid, and adrenocorticotropic hormones. However, increased prolactin serum concentration doesn’t always cause galactorrhea. Additional factors that may precipitate this disorder include the following: ❑ endogenous: pituitary (high incidence with chromophobe adenoma), ovarian, or adrenal tumors and hypothyroidism; in males, pituitary, testicular, or pineal gland tumors ❑ idiopathic: possibly from stress or anxiety, which causes neurogenic depression of the prolactin-inhibiting factor ❑ exogenous: breast stimulation, genital stimulation, or drugs (such as hormonal contraceptives, meprobamate, and phenothiazines).
A doctor will test for prolactin blood levels in women with unexplained milk secretion (galactorrhea) or irregular menses or infertility, and in men with impaired sexual function and, in rare cases, milk secretion. If prolactin is high, a doctor will test thyroid function and ask first about other conditions and medications known to raise prolactin secretion. While a plain X-ray of the bones surrounding the pituitary may reveal the presence of a large macro-adenoma, the small micro-adenoma will not be apparent. Magnetic resonance imaging (MRI) is the most sensitive test for detecting pituitary tumors and determining their size. MRI scans may be repeated periodically to assess tumor progression and the effects of therapy. Computed Tomography (CT scan) also gives an image of the pituitary, but it is less sensitive than the MRI. In addition to assessing the size of the pituitary tumor, doctors also look for damage to surrounding tissues, and perform tests to assess whether production of other pituitary hormones is normal. Depending on the size of the tumor, the doctor may request an eye exam with measurement of visual fields. The hormone prolactin is downregulated by dopamine and is upregulated by estrogen. A falsely-high measurement may occur due to the presence of the biologically-inactive macroprolactin in the serum. This can show up as high prolactin in some types of tests, but is asymptomatic.
Two drugs that have been used are the dopamine agonists cabergoline and bromocriptine.