Pituitary: Conditions

Pituitary tumors, also called pituitary adenomas, are the most common cause of pituitary gland disorders. More than 99 percent of these tumors are benign. Most pituitary adenomas are known as non-functional adenomas and do not produce excessive amounts of hormones, while others can result in hormone overproduction, causing serious endocrine problems, such as acromegaly (GH excess), Cushing's syndrome (ACTH excess) or prolactinoma (prolactin excess).

Small pituitary adenomas (less than 1 cm in diameter, or smaller than a grape) are called microadenomas, while larger tumors are called macroadenomas. As pituitary tumors grow, they can compress the pituitary gland and cause decreased hormone production (pituitary insufficiency, or hypopituitarism). They can also compress the optic nerve, causing visual problems and headaches.

Other conditions can also result in pituitary problems. Tumors in the pituitary region, infections, and autoimmune conditions can affect the pituitary gland and cause headaches, visual problems, and hormonal abnormalities. Select a link below to learn more:

Small, non-functional pituitary adenomas or tumors (2-3 mm in size) occur in about 10 percent of the population and are usually detected during brain imaging conducted for a different reason (pituitary incidentalomas). These small pituitary tumors usually do not cause any problems; however, if small pituitary tumors grow, problems may arise so clinical supervision is necessary upon discovery of these tumors.

With larger non-functional pituitary tumors, patients often experience headaches, vision problems, and symptoms of pituitary insufficiency. Vision problems are a serious complication of pituitary tumors and usually begin with loss of peripheral vision. If untreated, vision problems typically progress to blindness. However, if pituitary tumors are caught early enough and treated surgically, vision usually improves.

Pituitary tumors causing hormonal excess are called functioning pituitary tumors. Acromegaly, Cushing's disease and prolactinomas are the most common. 

Acromegaly

Acromegaly is caused by a pituitary tumor that produces excess growth hormone (GH). It most commonly affects middle-aged adults and can result in serious illnesses or premature death. If the disease develops before a person has stopped growing, it causes gigantism since too much GH promotes the growth of bones in the body. The most common symptoms of GH excess are enlargement of the hands, feet, and face and excessive sweating. Patients may also experience headaches, irregular periods (in women), impotence (in men), and peripheral vision loss. Patients may also have an enlarged heart, tingling or pain in extremities (peripheral neuropathy), and excessive sleepiness during the day (sleep apnea). Because of its slow onset, acromegaly may go undiagnosed for many years. Once recognized, acromegaly is treatable in most patients. The primary treatment is usually surgery followed by radiotherapy or medications that decrease GH excess.

Cushing's Disease

Cushing's disease refers to a pituitary adenoma that produces excess ACTH, which stimulates cortisol secretion by the adrenal glands located above each kidney. Patients with Cushing's disease have progressive weight gain, muscle weakness, easy skin bruising, impotence (in men), irregular periods (in women), and depression. Patients also have high blood pressure, diabetes, and osteoporosis. Many of these problems are non-specific, meaning that people who have them may not have Cushing's disease. On the other hand, most patients who have Cushing's disease exhibit some, if not all, of these symptoms.

There is a characteristic appearance in many patients with Cushing's disease which includes a round face, the excess fat pad in the back of the neck ("buffalo hump"), excess fat in the collarbone area, weight gain primarily in the abdominal region with relative thinning of the arms and legs, and red abdominal stretch marks.

Diagnosis of Cushing's disease is sometimes challenging and has to be done by an experienced endocrinologist. The treatment is usually pituitary surgery, which needs to be done by an experienced neurosurgeon. Radiotherapy may be used in some patients that are not cured by surgery. Medical therapy plays a limited role in the management of Cushing's disease. In the majority of cases, surgical curative treatment of Cushing's disease leads to improvement of most of the symptoms mentioned.

Prolactinomas

Prolactinomas are benign tumors of the pituitary gland that produce excessive amounts of the hormone prolactin. Symptoms result from too much prolactin in the blood (hyperprolactinemia) or pressure from the tumor on surrounding tissues (if the tumor is large). Hyperprolactinemia causes milk discharge from the breast (galactorrhea), menstrual irregularities (oligomenorrhea or amenorrhea) and infertility in women, and impotence in men. Prolactinomas are usually successfully treated with medications that shrink the tumor, even if large. Some prolactinomas require surgery. Hyperprolactinemia does not mean that the patient has a pituitary tumor since it can occur in patients who take certain medications or have other medical conditions. Evaluation by an endocrinologist is necessary to differentiate these conditions.

The pituitary gland produces a number of hormones, which are released into the blood to control other glands in the body (thyroid, adrenal, ovary, or testicles). If the pituitary is not producing one or more of these hormones, the condition is called hypopituitarism. If all the hormones produced by the anterior pituitary are decreased, the condition is called panhypopituitarism. Hypopituitarism is most often caused by large benign tumors of the pituitary gland, or of the brain in the region of the hypothalamus. Pituitary underactivity may be caused by the direct pressure of the tumor mass on the normal pituitary or by the effects of surgery or radiotherapy used to treat pituitary tumors.

Less frequently, hypopituitarism can be caused by infections in or around the brain (such as meningitis) or by severe blood loss, head injury, or by other rare diseases. Some of the clinical features that may be associated with hypopituitarism include excessive tiredness and decreased energy, irregular periods (oligomenorrhea) or loss of normal menstrual function (amenorrhea), impotence (in men), infertility, increased sensitivity to cold, constipation, dry skin, low blood pressure, and lightheadedness upon standing (postural hypotension). Treatment of hypopituitarism consists of long-term hormone replacement therapy since pituitary hormone deficits are rarely reversed after tumor removal.

Although pituitary tumors are the most common cause of pituitary gland disorders, other conditions can also result in pituitary gland problems.

Tumors in the pituitary region other than pituitary adenomas

• Craniopharyngiomas, cysts and meningiomas are examples of tumors that originate in the proximity of the pituitary gland and may cause hypopituitarism, headaches, visual and neurological problems. These tumors may be large and difficult to remove completely. Postoperative radiation therapy is often necessary for craniopharyngiomas and meningiomas.

Non-tumoral pituitary diseases

• Empty sella syndrome occurs when cerebrospinal fluid is found in the sellar space that is normally occupied by the pituitary gland. This condition can occur spontaneously or after treatment of a pituitary tumor with surgery, medications or radiation. Empty sella is sometimes associated with hypopituitarism and requires hormonal replacement.
• Non-tumor pituitary diseases like sarcoidosis, histiocytosis and hemochromatosis can infiltrate the pituitary gland and cause pituitary hormone imbalances.
• Rarely, infections or autoimmune conditions affect the pituitary gland causing hypophysitis, also characterized by hormonal abnormalities.

At Emory, our doctors are experts in the diagnosis and treatment of all pituitary-related conditions.