The pituitary gland is situated beneath the cerebral cortex. It releases hormones that control much of the body's metabolism. Pituitary tumors are usually benign, meaning non-cancerous. Their effects are caused by the hormones they release and by pressure on adjacent structures. Different types of tumors release different hormones, and symptoms will vary accordingly.
Prolactinomas
Tumors that secret prolactin can cause galactorrhea, which is discharge of milk form the breast, irregular periods and absence of periods. In men, an excess of prolactin can cause symptoms that include enlarged breasts, impotence and infertility.
Growth Hormone Secreting Tumors
In children and adolescents, an excess of growth hormone can lead to gigantism. In adults, excessive growth hormone leads to acromegaly. Symptoms include coarse facial features and a protruding lower jaw. Proliferation of cartilage and fibrous tissue lead to compression of nerves. Acromegaly is one cause of bilateral carpal tunnel syndrome. Internal organs are enlarged. According to the Merck Manual, the risk of death from cardiac disease is double that of the normal population. Additional symptoms include a thickened voice and an increased risk of cancer, especially of the gastrointestinal tract.
Cushing's Syndrome
The pituitary secretes ACTH, or adrenocorticotrophic hormone, which stimulates the adrenals to release cortisol. Pituitary adenomas cause a majority of Cushing's syndrome cases. Excess cortisol leads to high blood pressure; striae, which are stretch marks in the abdomen; and redistribution of fat. The fat accumulates in the abdomen and between the scapulas, causing what is known as a "Buffalo hump." Excess cortisol can also lead to high blood sugar and bone loss.
Vision Effects
A large pituitary tumor will press on the optic nerves. Typically the first symptom is loss of peripheral vision. Untreated, it may lead to blindness. According to "Harrison's Principles of Internal Medicine," tumors may compress other cranial nerves and cause double vision, inability to move the eyes, drooping of the eyelid and decreased facial sensation.
Pituitary Apoplexy
Pituitary apoplexy can occur when a large tumor suddenly compresses its own blood supply. The result is a sudden headache, vomiting, paralysis of eye movement, vision impairment and cessation of pituitary hormone production. This is a medical emergency. Treatment includes medical stabilization, which includes replacement of hormones such as cortisol, to be then followed by neurosurgical intervention.
References
- Merck Manual Professional: Gigantism and Acromegaly
- MayoClinic.com: Pituitary Tumors
- "Harrison's Principles of Internal Medicine, 17th Edition"; Antoni Fauci (ed); 2008
