Content Reviewers:Rishi Desai, MD, MPH
With gigantism, “gigant” refers to giant, so gigantism is a rare hormonal disorder in children and adolescents where there is an excess of growth hormone, and it causes rapid and excessive growth of long bones, like the tibia and humerus.
As an example, the French wrestler André the Giant who played Fezzik in the movie The Princess Bride had gigantism.
Normally, the hypothalamus which is at the base of the brain, secretes growth hormone-releasing hormone in bursts throughout the day - every couple hours, and this can increase based on things like low blood glucose levels, lack of food, increased exercise, increased sleep, and increased stress like trauma.
The growth hormone-releasing hormone goes into the hypophyseal portal system - which is a network of capillaries linking the hypothalamus to the anterior pituitary which is smaller in size than a pea.
An important indirect effect, is that growth hormone stimulates certain tissues like the liver, skeletal muscles, bones, and kidneys to produce somatomedin C, also called insulin-like growth factor 1.
Insulin-like growth factor 1 promotes cellular metabolism, prevents cell death, and helps cell divide and differentiate throughout the body. It’s also the key hormone that stimulates the growth in length of long bones.
This specific type of tumor is usually benign, meaning that it doesn’t invade into neighboring tissues.
These tumor cells continuously make excess growth hormone and that in turn leads to excess insulin-like growth factor 1 as well.
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