How common is a pituitary tumor?

Anthony P. Heaney, MD
Endocrinology Diabetes & Metabolism
Pituitary tumors are relatively common, affecting one in five individuals. However, it is important to note that whereas up to 20 percent of patients can have a pituitary abnormality noted on a brain imaging study such as a computed tomography (CT) scan or magnetic resonance imaging (MRI), the vast majority of those, often very small lesions (3 to 4mm), do not cause symptoms and do not require any treatment. Therefore, approximately only one in 1,000 people with a pituitary tumor will require treatment of some type.
Marvin Bergsneider, MD
You may read on the internet that one in five people have pituitary tumors. This is based on autopsy studies of generally older people. When a pathologist dissects the pituitary gland, they can find tiny, microscopic pituitary tumors that really aren't of any significance. For that reason, the one in five figure is really misleading.

When researchers looked at large populations who had had magnetic resonance imaging (MRI) scans of the brain, they looked at how many incidental pituitary tumors they could find. About one in 1,000 pituitary tumors were discovered in this way. That correlates with what doctors see in the general population.
Pituitary tumors are common, although there is some debate about how common they are. One large study estimated that 17 out of 100 people have one. However, the vast majority of these growths are benign, meaning that they not cancerous. Also, many people never experience any symptoms and therefore never receive a diagnosis for their tumor unless it is done posthumously.
It is estimated that 10-25 percent of the US population has some form of small pituitary tumor, an adenoma 2-3mm, but most of these people suffer no ill effects from the tumor. Although they can occur in any age patient, most of the tumors are found in older people and are more common in women than in men. The causes for the vast majority of pituitary tumors are unknown.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.