More than 95% of people who have acromegaly have a pituitary gland tumour called an adenoma.1 An adenoma is a tumour made up of abnormal gland cells, and these gland cells may release, or secrete, hormones. In acromegaly, the adenoma secretes growth hormone (GH) into the bloodstream. Too much GH produced by the adenoma and high levels of IGF-1 hormone produced as a result, lead to the symptoms of acromegaly.
Pituitary adenomas are benign, meaning not cancerous, and they do not spread to other parts of the body. They do, however, continue to grow and secrete hormones.
Less than 5% of people who have acromegaly have a different type of tumour that also produces too much GH or GHRH (growth-hormone-releasing hormone).1 These tumours are not in the pituitary gland but can be found elsewhere in the body such as the hypothalamus, lung, pancreas or adrenal glands.
In both cases, complete removal of the tumour can cause GH release to return to normal.
Changes in DNA
Doctors do not know the exact reason why adenomas develop in the pituitary gland. Most cases of acromegaly are not hereditary, or passed on by your family, but still result from changes in the DNA of the pituitary gland.
The DNA changes make the adenoma keep growing. The adenoma may become very large and start to grow around other parts of the brain.
Pituitary adenomas can continue to grow and release GH
Check out the true-2-me guest editorial on treatment Considerations for Acromegaly