ConditionHormones & metabolism
Pituitary Adenoma
A pituitary adenoma is a noncancerous tumor of the pituitary gland, the pea-sized gland at the base of the brain that controls many other hormone glands. Adenomas are common, and many are small and found by chance on scans. Some produce excess hormones, causing conditions such as prolactinoma, acromegaly or Cushing's disease. Larger ones can press on the optic nerves, causing loss of side vision, or stop the gland making normal hormones. Treatment includes medicines, surgery through the nose and radiotherapy.
Also called: Pituitary tumor, pituitary neoplasm, adenoma of the pituitary gland, pituitary neuroendocrine tumor (PitNET)
At a glance
- What it is
- A benign tumor of the pituitary gland.
- Size
- Microadenoma (under 1 cm) or macroadenoma (1 cm or more).
- Types
- Prolactinoma (most common), nonfunctioning, growth hormone (acromegaly), ACTH (Cushing's disease), TSH-secreting.
- Symptoms
- Hormone excess or deficiency, headaches, and loss of side vision from pressure on the optic chiasm.
- Treatment
- Cabergoline for prolactinomas. Transsphenoidal surgery for most others. Radiotherapy and medicines for residual disease.
When to get help
Call 911 or go to the ER
- Sudden severe headache with vomiting, vision loss, double vision, drooping eyelid or confusion (possible pituitary apoplexy: bleeding into the tumor)
- Severe weakness, low blood pressure, vomiting and confusion in someone with known pituitary disease (possible adrenal crisis)
See a doctor within a day or two
- Gradual loss of side vision, bumping into things on both sides
- Extreme thirst and passing large volumes of dilute urine
Book a routine appointment
- Milky nipple discharge, missed periods or reduced libido
- Enlarging hands, feet or jaw, changed facial features, or new snoring
- Weight gain in the face and trunk with purple stretch marks and easy bruising
- A pituitary lesion found incidentally on a scan
What the pituitary does
The pituitary sits in a bony pocket (sella turcica) just below the optic chiasm, where the optic nerves cross. It makes hormones that control:
- the thyroid (TSH)
- the adrenal glands (ACTH)
- growth (growth hormone)
- the ovaries and testes (LH and FSH)
- breast milk production (prolactin)
Its back part stores antidiuretic hormone, which controls water balance.
Types of pituitary adenoma
| Type | Hormone | Main effects |
|---|---|---|
| Prolactinoma | Prolactin | Missed periods, milky discharge, infertility, low libido, erectile dysfunction |
| Nonfunctioning adenoma | None | Pressure effects and hormone deficiency |
| Somatotroph adenoma | Growth hormone | Acromegaly in adults, gigantism in children |
| Corticotroph adenoma | ACTH | Cushing's disease: weight gain, high blood pressure, diabetes, bruising |
| Thyrotroph adenoma | TSH | Overactive thyroid symptoms (rare) |
| Gonadotroph adenoma | FSH or LH | Usually behaves as nonfunctioning |
How common
Pituitary adenomas are found in roughly 1 in 1,000 people clinically, and small ones are seen far more often on brain scans done for other reasons. Most are benign and slow-growing. True pituitary cancer is very rare.
Symptoms
From hormone excess
Depend on the type, as listed above.
From pressure (mainly macroadenomas)
- headaches
- loss of side vision in both eyes (bitemporal hemianopia), often unnoticed until advanced
- double vision or a drooping eyelid if nerves beside the pituitary are affected
From hormone deficiency (hypopituitarism)
- tiredness and weakness (adrenal and thyroid deficiency)
- loss of periods, low libido, infertility
- low mood, feeling cold
- poor growth in children
Pituitary apoplexy
Sudden bleeding or loss of blood supply within an adenoma causes a severe headache, vision loss and sometimes life-threatening adrenal deficiency. It is an emergency.
Diagnosis
- MRI of the pituitary with contrast
- hormone blood tests: prolactin, IGF-1 (growth hormone), cortisol tests such as late-night salivary cortisol or dexamethasone suppression, TSH and free T4, LH, FSH, testosterone or estradiol
- visual field testing by an ophthalmologist
- tests for diabetes insipidus if thirst and urination are excessive
Very high prolactin with a large tumor strongly suggests a prolactinoma. Mildly raised prolactin can come from pressure on the pituitary stalk by a nonfunctioning tumor.
Treatment
Prolactinomas
- dopamine agonists: cabergoline (preferred) or bromocriptine, which lower prolactin and usually shrink the tumor
- surgery for those who cannot tolerate or do not respond to medicine
Other adenomas
- transsphenoidal surgery: removal through the nose and sphenoid sinus, without opening the skull, by an experienced pituitary neurosurgeon
- medicines: somatostatin analogues, pegvisomant or cabergoline for acromegaly. Cortisol-lowering drugs for Cushing's disease
- radiotherapy or stereotactic radiosurgery for residual or recurrent tumors
Small nonfunctioning microadenomas
Often monitored with periodic MRI and hormone tests, without treatment.
Hormone replacement
Any hormone deficiencies are replaced: hydrocortisone, levothyroxine, sex hormones, growth hormone and desmopressin as needed. People on hydrocortisone need sick-day rules and an emergency injection kit.
Outlook
Most pituitary adenomas are controlled with treatment. Prolactinomas usually respond very well to medicine. Surgical cure rates are high for small tumors in experienced centers. Lifelong follow-up checks for regrowth and hormone balance.
Frequently asked questions
What is a pituitary adenoma?
A pituitary adenoma is a benign tumor of the pituitary gland. It may produce excess hormones, cause hormone deficiencies, or press on nearby structures such as the optic nerves. Many small adenomas cause no problems.
What are the symptoms of a pituitary adenoma?
Symptoms depend on type and size: missed periods and milky discharge (prolactinoma), enlarged hands and feet (acromegaly), weight gain and high blood pressure (Cushing's), headaches, loss of side vision, tiredness and low libido.
Is a pituitary adenoma cancer?
No. Pituitary adenomas are almost always benign and do not spread. They can still cause serious problems through hormone changes or pressure on nearby structures, so they need assessment and sometimes treatment.
How is a pituitary adenoma treated?
Prolactinomas are usually treated with cabergoline. Most other symptomatic adenomas are removed through the nose (transsphenoidal surgery). Radiotherapy and medicines treat leftover tumor. Small nonfunctioning tumors may simply be monitored.
Can a pituitary adenoma affect vision?
Yes. A large adenoma can press on the optic chiasm, causing gradual loss of side vision in both eyes. Sudden vision loss with a severe headache can signal pituitary apoplexy, which is an emergency.
Sources
This guide was written from current patient and clinical guidance, including:
- Endocrine Society: Clinical practice guidelines on pituitary incidentaloma, hyperprolactinemia and acromegaly
- Pituitary Society: Consensus statements
- National Cancer Institute: Pituitary tumors treatment (PDQ)
- American Association of Neurological Surgeons: Pituitary gland tumors
- NIDDK: Prolactinoma; Acromegaly; Cushing's syndrome