A pituitary adenoma — recently reclassified by the World Health Organization as a pituitary neuroendocrine tumor (PitNET) — is a benign growth arising from the hormone-producing cells of the anterior pituitary gland. Imaging and autopsy series estimate that 10-25% of adults have a small pituitary lesion, but clinically relevant adenomas affect approximately 1 in 1,000 to 1 in 1,400 people.
A pituitary adenoma (ICD-10: D35.2 benign neoplasm of pituitary gland; D44.3 neoplasm of uncertain behavior; updated 2022 WHO terminology pituitary neuroendocrine tumor, PitNET) is a benign monoclonal growth arising from the anterior pituitary gland. The vast majority are histologically benign, but some demonstrate aggressive behavior with rapid growth, invasion of surrounding structures, or recurrence after treatment; very rare cases (under 0.2%) metastasize and are termed pituitary carcinoma. Adenomas are classified by two main features. By size: microadenoma <10 mm, macroadenoma ≥10 mm, giant adenoma ≥40 mm.
The key symptoms of Pituitary Adenoma are: Headache, often retro-orbital or bitemporal, present in 40-60% of patients with macroadenomas from dural stretch or cavernous sinus invasion., Bitemporal hemianopia (loss of peripheral vision in both eyes) from compression of the optic chiasm by a suprasellar extension of the adenoma — classic finding in macroadenomas., Galactorrhea (milk discharge from breasts in non-pregnant women or in men) and irregular menstruation or amenorrhea in women with prolactinoma., Loss of libido, erectile dysfunction, and decreased facial/body hair in men with hyperprolactinemia or secondary hypogonadism from any adenoma., Acromegaly features: increasing shoe and ring size, coarsening facial features (prominent jaw, enlarged nose and lips), excessive sweating, large hands and feet, joint pain, hypertension, sleep apnea, and new diabetes — from growth hormone excess., Cushing's syndrome features from ACTH-secreting adenoma: central obesity with thin extremities, moon facies, purple striae, easy bruising, proximal muscle weakness, hypertension, diabetes, osteoporosis, and mood instability., Diplopia (double vision) and other cranial nerve palsies from cavernous sinus invasion or apoplexy — affects nerves III, IV, V1, V2, VI..
Evaluation starts with the clinical syndrome: hormone-excess features (galactorrhea, acromegaly, Cushing's syndrome, central hyperthyroidism), hormone-deficiency features (hypopituitarism), or mass-effect features (headache, visual field loss, cranial nerve palsy). Hormone testing includes serum prolactin (with dilution to exclude hook effect in very high values), IGF-1 and oral glucose tolerance test with growth hormone suppression for acromegaly, late-night salivary cortisol and 24-hour urine free cortisol or dexamethasone suppression test for Cushing's, free T4 with TSH for central hyperthyroidism or hypothyroidism, LH/FSH and gonadal steroids, and morning cortisol for adrenal axis. Baseline pituitary panel for any adenoma includes prolactin, free T4, TSH, ACTH, cortisol, LH/FSH, estradiol or testosterone, IGF-1, and serum sodium and osmolality. MRI of the pituitary with thin sections, dynamic contrast enhancement, and dedicated coronal and sagittal views is the imaging gold standard; CT is used when MRI is contraindicated. Visual field testing by automated perimetry (Humphrey, Octopus) is performed in any patient with a tumor near the optic chiasm. The Knosp grade rates cavernous sinus invasion (0-4) and influences surgical resectability. Petrosal sinus sampling (IPSS) is used to localize ACTH source when biochemistry confirms Cushing's but MRI is negative or equivocal. Genetic testing is recommended for early-onset (under 30), familial, or aggressive adenomas. Multidisciplinary pituitary clinic review by endocrinology, neurosurgery, neuro-ophthalmology, and radiation oncology produces an integrated plan.
Most pituitary adenomas are benign and amenable to effective treatment. Prolactinoma: 80-90% achieve normal prolactin with cabergoline; long-term remission off treatment after 2-3 years achieved in 30-40% of patients with sustained normalization and no residual tumor on MRI. Non-functioning macroadenoma: gross total resection 50-80% at first surgery; tumor recurrence rate 10-30% over 10 years, often controlled by stereotactic radiosurgery. Acromegaly: surgical remission rates 70-90% for microadenomas, 40-60% for macroadenomas; combined surgery and medical therapy achieves biochemical control in 80-90%. Mortality in untreated acromegaly is 2-3× general population from cardiovascular and metabolic causes; effective treatment normalizes life expectancy. Cushing's disease: surgical remission 70-90% in microadenomas, 60-70% in macroadenomas; recurrence in 15-30% over 10 years. Untreated Cushing's has 5-year mortality up to 50%; treated, mortality approaches that of general population. Hypopituitarism develops in 20-40% over 10 years after surgery or radiotherapy and requires lifelong hormone replacement. Pituitary carcinoma is rare (under 0.2%) but aggressive. Aggressive (refractory) PitNETs by 2022 WHO terminology may require chemotherapy (temozolomide) or experimental approaches.
Pituitary adenoma care requires close collaboration between endocrinology, neurosurgery, neuro-ophthalmology, and radiation oncology. High-volume pituitary centers achieve substantially better surgical remission rates (10-30 percentage points higher than low-volume centers) and lower complication rates. Multidisciplinary pituitary tumor boards make balanced recommendations weighing tumor characteristics and patient factors.
Find specialists →Transsphenoidal surgery: hospital stay typically 2-4 days; return to most activities at 4-6 weeks; full clearance at 8-12 weeks. Vision improves often within days to weeks if optic chiasm decompression is achieved. Hormone normalization for Cushing's and acromegaly within days to weeks of successful surgery. Tumor shrinkage on dopamine agonist for prolactinoma over 3-6 months. Stereotactic radiosurgery effect on hormone secretion over 2-10 years. Lifetime monitoring required.
Regular moderate aerobic activity (150 minutes per week) and resistance training (2 sessions per week) are encouraged. In acromegaly with cardiomyopathy or severe sleep apnea, exercise prescription should be reviewed with cardiology. In Cushing's syndrome with proximal myopathy and osteoporosis, supervised physical therapy initially. After transsphenoidal surgery, avoid heavy lifting and Valsalva maneuvers for 4-6 weeks to reduce CSF leak risk.
Choose an endocrinologist with documented pituitary expertise and a neurosurgeon at a high-volume center (typically >50 transsphenoidal cases per year per surgeon). Pituitary Society and Pituitary Network Association recognize centers with multidisciplinary capability. Confirm availability of endoscopic transsphenoidal surgery, dedicated pituitary MRI protocols, neuro-ophthalmology, and stereotactic radiosurgery.
Medically reviewed by AIHealz Medical Editorial Board · May 13, 2026
Ranked by patient outcomes and specialized experience.
Verifying top specialists in Mexico.
Apply as specialist →Specialists who treat Pituitary Adenoma. Get expert guidance and personalized care.