Pituitary adenoma
A benign (non-cancerous) growth on the pituitary gland at the base of the brain. Some make excess hormones, causing distinctive syndromes; others are 'silent' but grow large enough to press on the gland or nearby nerves, causing headaches, visual loss and hormone deficiency.
What it is
A pituitary adenoma is a growth arising from the pituitary gland. Almost all are benign, but their effects come in two ways. First, some adenomas overproduce a pituitary hormone, causing a specific syndrome depending on which: a prolactin-secreting tumour (prolactinoma) raises prolactin, causing milky discharge, loss of periods or low libido; a growth-hormone-secreting one causes acromegaly; an ACTH-secreting one causes Cushing's disease. Second, whether hormonally active or 'silent', an adenoma that grows large (a macroadenoma) can press on structures nearby — squeezing the rest of the pituitary to cause hormone deficiencies (hypopituitarism), and pushing on the optic nerves above to cause a characteristic loss of the outer fields of vision, along with headaches. Small tumours (microadenomas) are common and often found incidentally on brain scans. Diagnosis combines hormone tests to detect over- or under-production with an MRI of the pituitary. Management depends on the type: some prolactinomas shrink well with tablets, while others need surgery or radiotherapy, plus replacement of any deficient hormones.
Key lab markers
- Prolactin — markedly raised in a prolactinoma; mildly raised if a larger tumour disrupts the stalk.
- IGF-1 (and growth hormone) — raised in a growth-hormone-secreting tumour (acromegaly).
- ACTH and cortisol — raised in an ACTH-secreting tumour (Cushing's disease).
- TSH, free T4, LH, FSH — may be low if a large tumour causes hypopituitarism.
- MRI of the pituitary — the key imaging test (not a blood marker).
Symptoms
- Headaches
- Visual changes, classically loss of the outer (peripheral) fields of vision
- In a prolactinoma: milky nipple discharge, loss of periods, low libido
- In acromegaly: enlarging hands, feet and facial features
- In Cushing's disease: weight gain, easy bruising, high blood pressure
- Symptoms of hormone deficiency: tiredness, low libido, cold intolerance
- Often none — many are found incidentally
Related lab panels
When to discuss with a doctor
A pituitary adenoma is diagnosed and managed by an endocrinologist, usually with a neurosurgeon and eye specialist when the tumour is large. It matters because the hormone-secreting types cause treatable syndromes that are easy to miss, and because a large tumour can threaten vision and the rest of the pituitary. New or worsening headaches with visual changes — especially loss of side vision — need prompt assessment. Sudden severe headache with visual loss (pituitary apoplexy) is an emergency. A small tumour found by chance may simply be monitored. Mediora.AI can surface the hormone patterns that point to a functioning adenoma — a high prolactin, a high IGF-1, or a high ACTH and cortisol — prompting the right specialist workup and imaging; diagnosis and treatment belong with your endocrine team.