Overview

The pituitary gland is a small oval-shaped endocrine gland located at the base of the brain just behind the nose and below the optic nerve (the nerve which leads to the eye) . It is about the size of a pea and is very important because it secretes several chemical messages known as hormones.

Hormones produced by the pituitary gland helps to regulate and control the secretion of hormones from other endocrine glands which are responsible for the body's growth, metabolism and maturation.

Causes

The cause of pituitary tumours, like that of other brain tumours, is unknown.

Symptoms

1. Those caused by pressure on normal pituitary tissue so that it cannot deliver its normal production of hormones, e.g., general weakness and fatigue, apathy, pale complexion, loss of menstruation before menopause and loss of sexual function.

2. Those caused by pressure on structures around the pituitary, e.g., headaches, loss of vision.

3. Those caused by excessive hormone production:

• Prolactin Hormone: loss of menstruation (menopause) and inappropriate milk production by the breasts (galactorrhoea) and infertility in women; impotence and infertility in men.
• Growth Hormone: gigantism in children, and in adults who have reached their full height, condition is called acromegaly where the hands, feet and lower jaw becomes enlarged. Excessive growth hormone can aggravate diabetes mellitus, high blood pressure and heart disease.
• Excessive Adreno-corticotrophic hormone (ACTH): this stimulates the adrenal gland to make and secrete glucocorticoids. Excessive amounts of glucocorticoid hormones cause build-up of fat in the face (moon-face), neck, trunk and prominent stretch-marks appear. The arms and legs remain thin. The skin is hairy, thin and easily bruised. Excessive amounts of sugar in the blood (diabetes mellitus) and high blood pressure may occur.

Diagnosis

• Clinical history and examination
• CT Head Scan / MRI studies
• Endocrine evaluation
• Visual field examination

Treatment Options

There are three kinds of treatments available. The recommended treatment will depend on the type of tumour, its size and extent, and your age and overall health.

Surgery
This is done to remove the tumour. The preferred surgery is the trans-sphenoidal approach where the tumour is removed through the nasal passage via an incision in the mouth or nose. Another type of surgery is the craniotomy where a portion of bone in the skull is removed to gain access to the tumour. The bone is replaced following tumour removal.

Large tumours that extend outside the pituitary fossa may require the addition of radiation therapy.

Radiation Therapy
The commonest form of radiation therapy is standard external-beam radiation therapy where high energy X-rays are aimed at the tumour over 5-6 weeks to cause it to shrink. Radiosurgery (Gamma Knife treatment) using multiple radiation beams directed at the tumour has also been used to deliver a large single dose of radiation to stop it from growing.

Drug Therapy
Follow-up by an endocrinologist may be required :

1. to detect and replace hormone deficiencies that develop after treatment e.g., thyroxine and hydrocortisone tablets. This treatment is life-long and must be continued even in sickness.

2. to block hormone production from the tumour. This treatment is usually given when excessive amounts of hormones continue to be made despite surgery or radiation. Bromocryptine is given when the tumour produces large amounts of prolactin, and in addition to suppressing prolactin production may cause a dramatic shrinkage of the tumour. Somatostatin injections may be used for growth hormone producing tumours.

Recurrence
Regular follow-up with laboratory tests of hormone levels and X-ray studies such as MRI Scan are necessary to diagnose and treat recurrences. If recurrence is diagnosed, re-operation may be necessary. Large recurrence may require radiation therapy and or drug therapy as well.