Prolactinoma

A usually benign pituitary tumor that secretes excess prolactin. Elevated prolactin can disrupt reproductive function and, when the tumor is large, compress nearby structures.

Prolactin: A pituitary hormone that supports milk production and suppresses reproductive hormone signaling when elevated. Tumor cells release this hormone, driving most prolactinoma symptoms.
Serum prolactin measurement: A blood test that measures circulating prolactin concentration. It establishes the hormonal abnormality and helps distinguish a secreting tumor from other causes.
Pituitary gland: An endocrine gland beneath the brain that releases hormones regulating growth, reproduction, and other body functions. Prolactinomas arise from hormone-producing cells in this gland.
Medication-induced hyperprolactinemia: Elevated blood prolactin caused by drugs that interfere with dopamine signaling or prolactin regulation. Antipsychotics and some other medicines can raise prolactin without a secreting pituitary tumor.
Dopamine: A neurotransmitter that normally inhibits prolactin secretion from pituitary lactotroph cells. Reduced dopamine signaling can raise prolactin, while dopamine-mimicking drugs often shrink these tumors.
Magnetic resonance imaging: An imaging method that uses magnetic fields and radio waves to produce detailed pictures of internal structures. Pituitary MRI locates the tumor and measures its size and relationship to nearby structures.
Lactotroph: A pituitary cell that produces and secretes prolactin. Prolactinomas develop from these cells.
Primary hypothyroidism: Underactivity of the thyroid gland arising from dysfunction within the thyroid itself. It can raise prolactin through increased hypothalamic TRH signaling and may be reversible with thyroid treatment.
Hyperprolactinemia: An abnormally high concentration of prolactin in the blood, caused by tumors, medications, or other conditions. It is the biochemical state produced by a prolactinoma, though not every case has a tumor cause.
Cabergoline: A long-acting dopamine agonist used to lower prolactin and treat prolactin-secreting pituitary tumors. It is commonly used as first-line treatment and often reduces both hormone levels and tumor size.

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HyperprolactinaemiaBroader topic: It is a common pathological cause of persistent, marked prolactin elevation.