Pituitary adenoma arises from the pituitary gland, a hormone gland which controls most of the hormones in the body. It is always benign and does not transform to a malignant tumour. It may produce the following symptoms:
1) Over-secretion of hormones: the most common hormone overproduced is prolactin. In females, it causes breast discharge, irregularity or lack of menstruation or infertility; in males, it causes lack of sex drive or impotence. Other hormones overproduced may be growth hormone (in adult, it causes big hands, feet and head, night sweats and in children, excessive height) and ACTH (It may cause weight gain, moon face and hypertension)
2) Under-secretion of hormones (excessive tiredness and excessive urination, especially at night). This is due to severe compression of the pituitary gland when the tumour is large. It is estimated that 80% of the gland needs to be destroyed before the hormones become deficient.
3) Blurred vision due to compression of the eye nerves (optic nerve and chiasma) (patients may bump into things when walking past a door because of poor peripheral vision) and occasionally double vision.
4) Headache. This is uncommon but can happen due to stretching of the dura (covering on top of the pituitary gland).
Investigations often includes assessment of hormonal status (by an endocrinologist) and vision (by an eye doctor).
If the tumour secretes prolactin (prolactinoma, roughly about 20% of all pituitary tumour), often surgery is not needed. Treatment with drugs, bromocryptine or carbagoline, is often sufficient. Bromocryptine is an older drug and is usually taken daily. Carbagoline is a newer drug and can be taken once a week and is slightly more effective than bromocriptine but more expensive.
If the tumour is not a prolactinoma, surgery is often needed. It is often done through the nose (transphenoidal). A microscope and endoscope are used to help removal of the tumour. Traditionally, microscope is used which provides excellent magnified visualisation of the tumour. In recent years, endoscope is increasingly being used. Its advantage is a wider angle view than through a microscope but the risk of post-operative bleeding is slightly higher. Recovery after endoscopic surgery is faster with shorter hospital stay.
Occasionally, if the tumour is very large or grows towards one side, an operation through the head may be needed (subfrontal approach). Sometimes when the tumour grows into the blood vessels towards the side (cavernous sinus) or if the tumour regrows, radiotherapy is an effective way to shrink and control the tumour for long term. If the tumour is small, Gamma Knife is a good option of radiotherapy.
