Prolactinoma
Prolactinoma is a prolactin-secreting pituitary adenoma, the most common functional pituitary tumor, presenting with hypogonadism and galactorrhea from prolactin excess or with headache and visual loss from mass effect in larger tumors. Diagnosis requires an elevated prolactin with a pituitary mass on dedicated MRI after excluding pregnancy, medication effect, and hypothyroidism, and first-line treatment is a dopamine agonist, most often cabergoline, which lowers prolactin and shrinks the tumor without surgery in most patients.
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What this article covers
- Overview
A prolactin-secreting pituitary adenoma: prolactinoma is the most common functional (hormone-secreting) pituitary tumor, arising from lactotroph cells that autonomously produce prolactin independent…
- Epidemiology
The most common functional pituitary tumor, more frequent than growth hormone-, adrenocorticotropic hormone-, or thyroid-stimulating hormone-secreting adenomas.
- Risk factors
Female sex, associated with earlier presentation and detection at the microadenoma stage.
- Pathophysiology
Autonomous lactotroph proliferation: lactotroph cells within the tumor secrete prolactin independent of the tonic hypothalamic dopaminergic inhibition that normally restrains prolactin release.
- Clinical features
Amenorrhea or oligomenorrhea and galactorrhea in women, the classic presentation, often prompting evaluation while the tumor is still small.
- Differential diagnosis
Medication-induced hyperprolactinemia: typically produces a lower prolactin (25 to 100 ng/mL with typical antipsychotics), and normal pituitary imaging or, when a microadenoma is coincidentally…
- Diagnosis
The diagnosis requires a confirmed elevated prolactin with a discrete pituitary adenoma on dedicated MRI, only after pregnancy, medication effect, and hypothyroidism have been excluded, since the…
- Management
First, start a dopamine agonist for any prolactinoma causing hypogonadism, galactorrhea, infertility, or mass effect, since medical therapy is first-line and avoids surgery in most patients.
- Complications
Infertility, from prolactin-mediated gonadotropin suppression, often reversible with dopamine agonist therapy.
- Prognosis
Excellent for microadenomas, which respond well to dopamine agonist therapy with normalization of prolactin and resolution of hypogonadal symptoms in most patients.
- Prevention
Exclude pregnancy, medication effect, and hypothyroidism before diagnosing a prolactinoma, to avoid unnecessary dopamine agonist therapy or surgery for a reversible cause.
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Related articles
- Hyperprolactinemia
Hyperprolactinemia is an elevated serum prolactin level with causes ranging from physiologic states and medications to hypothyroidism, renal failure, and a prolactin-secreting pituitary tumor. Diagnosis requires a confirmed elevated prolactin with exclusion of pregnancy, medication effect, and hypothyroidism before attributing the finding to a pituitary adenoma, and first-line treatment for a symptomatic pituitary cause is a dopamine agonist such as cabergoline.
- Nonfunctioning pituitary adenoma
A nonfunctioning pituitary adenoma is a benign pituitary tumor, usually of gonadotroph origin, that does not secrete a clinically excessive hormone and presents through mass effect (visual field loss, headache) or hypopituitarism rather than a hypersecretory syndrome. Diagnosis requires excluding hormone excess and screening for hypopituitarism; treatment is observation for a small asymptomatic incidentaloma or transsphenoidal surgery for mass effect, apoplexy, or growth on follow-up.
- Pituitary apoplexy
Pituitary apoplexy is sudden hemorrhage or infarction of a pituitary adenoma causing severe headache, visual loss, ophthalmoplegia, and acute adrenocorticotropic hormone (ACTH) deficiency, and is a medical emergency. First-line treatment is immediate IV hydrocortisone given empirically before confirmatory testing when adrenal insufficiency is suspected, with urgent pituitary MRI and surgical decompression reserved for progressive visual loss.