Growth hormone stimulates growth in children, and muscle enlargement in adults. The excess production of growth hormone in adulthood results in acromegaly. Growth hormone is produced by the pituitary gland, which is in the brain.

Causes of acromegaly include:

• Tumors that produce growth hormone:
• Pituitary tumor
• Tumors that stimulate the pituitary gland:
• Pancreatic cancer
• Carcinoid tumor
• Lung cancer
• Adrenal tumor