The pituitary gland is situated at the base of the brain and produces many hormones which control growth in the body, sexual development and even water balance in the body. It also produces hormones which govern other hormone secreting glands like the thyroid gland. A tumour in the pituitary gland can result in the gland either over-producing or under-producing hormones, which can alter the functioning of different body organs, and even change the appearance of a person.
Pituitary gland tumours are not common, but when they do occur, they are usually in the front part of the gland and they are benign, that is they are not cancerous. Not much is known about the causes of a pituitary tumour, but some studies suggest that it may be hereditary and associated with the condition called multiple endocrine neoplasia. A majority of them produce an excess of prolactin. Over-production of this hormone causes infertility in women and erectile dysfunction in men. Some pituitary tumours produce growth hormones, which can lead to the increase in size of some parts of the body, while others produce hormones that cause extra stimulation of the adrenal glands, which can lead to changes in the chemical compositions in the body and can even alter the physical appearance of a person.
When the tumour starts growing, it exerts pressure on the optic nerve situated above the gland, and this can cause headaches, or even a partial loss of the field of vision. When it is large it may cause damage to the cells surrounding it, and this can lead to a reduction in the production of other pituitary hormones. A reduction in the production of hormones which stimulate the thyroid gland can cause hypothyroidism. On the other hand, a tumour which exerts pressure on the back part of the pituitary gland can reduce the production of vasopressin, a hormone which regulates water balance in the body.
Diagnosis and treatment
Blood tests can reveal low or excess levels of pituitary hormones in the body. MRI or CT scanning can also reveal the presence of this tumour. Sometimes, this tumour is discovered while tests are being carried out for other unrelated conditions. In such an event, the tumour is constantly monitored, without any treatment being given unless it is found to be growing. Some of them can be treated with drugs, but some may have to be removed by surgery. When it is not possible to remove the whole tumour even surgically, radiotherapy treatment is given to prevent it from growing any further. However, this radiotherapy treatment may result in a condition called hypopituitarism, which may require hormone replacement for life.