Pituitary Gigantism

What Is It?

Gigantism is the name for the clinical syndrome which arises from a growth hormone secreting pituitary tumor in childhood. This is caused by a pituitary adenoma which secretes high levels of growth hormone. However, the term itself can be used to describe other forms and causes of exceptional stature besides pituitary causes.

Growth hormone is important for many aspects of development and metabolism. In early development it causes profound growth of long bones and is responsible in part for normal stature. Therefore, if a child who is still growing is exposed to higher than normal levels of growth hormone, as in the case of this syndrome, they will grow to an abnormally tall stature. These individuals are sometimes referred to as pituitary giants.

Gigantism is the unique situation in which a growth hormone secreting adenoma occurs before an individual stops growing. After the end of growth, when the "growth plates" in the long bones fuse, increase in height is no longer possible. If a tumor such as this occurs after this point, in adult life, the patient will not grow in height but bones and features may become thickened and coarse. This syndrome, although caused by the same type of tumor just at a different point in life, is called Acromegaly.

Many famous people have suffered from gigantism and/or acromegaly. A couple notable examples are Andre the Giant and Richard Kiel ("Jaws" in the James Bond movies).

What Types of Symptoms Are Typical?

In addition to symptoms which may present with any pituitary tumor, such as headache, loss of visual function and hypopituitarism, patients with excess growth hormone secretion experience profound growth in stature. In addition, growth hormone can cause other metabolic and physiologic changes such as high blood glucose (diabetes mellitus) and high blood pressure.

How Is The Diagnosis Typically Made?

As with other pituitary adenomas the diagnosis is made through imaging studies such as an MRI scan as well as blood testing to evaluate pituitary hormonal function. These tests will reveal very high levels of growth hormone as well as its downstream hormone, insulin-like growth factor (IGF-1).

What Are Some Common Treatments?

For the most part, the mainstay of treatment for pituitary tumors is transsphenoidal surgery to remove the tumor. In the case of growth hormone secreting tumors, a couple of drugs are occasionally used in some patients. These include the dopamine agonists (bromocriptine) and somatostatin agonists (octreotide and lanreotide). While these may show some anti-tumor effects in some patients, they are not effective for everyone.

Each tumor and patient is different, so it is hard and inappropriate to make generalizations about what treatment plan is most appropriate. Each patient should discuss their options with their own physician team. See the pituitary adenoma page for more general information about tumors of the pituitary gland.

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Important Note: This site is not intended to offer medical advice. Every patient is different, and only your personal physician can help to counsel you about what is best for your situation. What we offer is general reference information about various disorders and treatments for your education.

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