Pituitary Gland Tumors Explained — Symptoms, Diagnosis, and Treatment Options

What the Pituitary Gland Does

The pituitary is often called the master gland because it produces hormones that control other glands throughout your body. It sits in a small bony pocket called the sella turcica, directly behind the bridge of your nose. Despite being smaller than a chickpea, it produces at least eight major hormones.

Growth hormone controls body growth and metabolism. Thyroid-stimulating hormone (TSH) tells your thyroid to produce hormones. ACTH tells the adrenal glands to produce cortisol. Prolactin stimulates breast milk production. LH and FSH control reproductive function. ADH regulates water balance. Oxytocin is involved in labor, breastfeeding, and social bonding.

When a tumor grows in the pituitary, it can overproduce one or more of these hormones, underproduct them by compressing normal tissue, or cause problems simply by growing large enough to press on nearby structures like the optic nerves.

Types of Pituitary Tumors

Over 99 percent of pituitary tumors are benign adenomas — they do not spread to other parts of the body. They are classified by size: microadenomas are smaller than 10 millimeters and macroadenomas are 10 millimeters or larger. They are also classified by whether they produce excess hormones (functioning) or not (non-functioning).

Prolactinomas are the most common type, overproducing prolactin. In women this causes irregular periods, unexpected breast milk production, and infertility. In men it causes decreased libido, erectile dysfunction, and sometimes breast enlargement. Because symptoms in men are subtler, prolactinomas are often diagnosed later and at larger sizes.

Growth hormone-producing adenomas cause acromegaly in adults — gradual enlargement of hands, feet, jaw, and facial features, along with joint pain, excessive sweating, and increased risk of diabetes and heart disease. In children before growth plates close, the same tumor causes gigantism.

ACTH-producing adenomas cause Cushing's disease — weight gain particularly in the face and abdomen, thin skin that bruises easily, purple stretch marks, muscle weakness, high blood sugar, high blood pressure, and mood changes. Non-functioning adenomas produce no excess hormones but can grow large enough to compress the normal pituitary and optic nerves.

Warning Signs to Watch For

Symptoms depend on which hormones are affected and whether the tumor is pressing on nearby structures. Vision changes are a critical warning sign — the optic nerves cross directly above the pituitary, and a growing tumor can compress them, causing loss of peripheral vision (tunnel vision) that often goes unnoticed until significant.

Persistent headaches, particularly those that do not respond to usual treatment, can result from pressure within the sella turcica. Unexplained hormonal changes — irregular periods, unexpected milk production, decreased sex drive, unusual fatigue, unexplained weight changes — should prompt investigation.

Many pituitary tumors are discovered incidentally when brain imaging is done for another reason. Studies suggest that small pituitary adenomas are present in up to 20 percent of the general population but most never cause symptoms or require treatment.

Diagnosis

Diagnosis involves blood tests measuring hormone levels and MRI of the brain focused on the pituitary region. MRI provides detailed images showing the tumor's size, location, and relationship to surrounding structures including the optic nerves and carotid arteries.

Comprehensive hormonal evaluation checks all pituitary hormones because even non-functioning tumors can compress normal tissue and reduce hormone production. Visual field testing maps your peripheral vision to detect any compression of the optic nerves.

If Cushing's disease is suspected, additional specialized tests are needed because cortisol levels fluctuate throughout the day. These may include 24-hour urine cortisol collection, late-night salivary cortisol tests, and dexamethasone suppression tests.

Treatment Options

Treatment depends on the tumor type, size, and symptoms. Prolactinomas are unique because they usually respond dramatically to medication alone. Drugs called dopamine agonists (cabergoline or bromocriptine) shrink prolactinomas in roughly 80 to 90 percent of cases, often normalizing prolactin levels and restoring fertility without surgery.

For other tumor types, transsphenoidal surgery is the primary treatment. The surgeon reaches the pituitary through the nose and sphenoid sinus — no external incision or opening of the skull. This approach has high success rates for microadenomas (80 to 90 percent cure rate) and lower but significant rates for macroadenomas. Recovery is typically one to two weeks.

Radiation therapy, including newer focused techniques like stereotactic radiosurgery (Gamma Knife), is used when surgery cannot completely remove the tumor or when the tumor recurs. It works gradually over months to years. Hormone replacement therapy is needed lifelong if the tumor or its treatment has damaged normal pituitary function.

Small, non-functioning adenomas that are not causing symptoms may simply be monitored with periodic MRI scans and hormone testing, a watch-and-wait approach appropriate when the risks of treatment outweigh the risks of observation.