Pituitary Adenoma
A pituitary adenoma is a non-cancerous growth that develops in the pituitary gland, a small structure at the base of the brain that controls many of the body’s hormones. These tumors can be small and silent or large enough to affect vision, hormone levels, and overall well-being. While most are benign, even small pituitary adenomas can have significant effects depending on the hormones they produce or the structures they press against.
What is it?
A pituitary adenoma forms when cells in the pituitary gland grow into a small tumor. Adenomas are classified by size—microadenomas are smaller than 10 millimeters, while macroadenomas are larger and more likely to press on nearby structures. They are also classified by whether they produce hormones (functioning) or not (non-functioning). Functioning adenomas can cause conditions such as Cushing’s disease, acromegaly, or elevated prolactin levels, while non-functioning adenomas tend to cause symptoms only when they grow large enough to compress surrounding tissue.
MRI is the preferred imaging test for evaluating the pituitary gland, providing detailed views of the tumor’s size, location, and effect on nearby structures such as the optic nerves. Dedicated pituitary MRI protocols with thin slices and contrast offer the clearest picture and help guide treatment decisions.
Important to Know
Many pituitary adenomas are discovered incidentally on imaging done for other reasons and never require treatment. When treatment is needed, options range from medication—often highly effective for prolactin-producing tumors—to minimally invasive surgery or targeted radiation. Regular imaging follow-up is common to monitor stability over time.
Red flag symptoms include sudden severe headache, rapid vision loss, double vision, or signs of hormonal crisis such as extreme fatigue, low blood pressure, or fainting—these may indicate pituitary apoplexy or another urgent condition requiring immediate evaluation.