Gigantism is abnormal growth due to an excess of growth hormone during childhood.
Giantism; Pituitary giant
The most common cause of too much growth hormone release is a noncancerous (benign) tumor of the pituitary gland. Other causes include:
- Carney complex
- McCune-Albright syndrome (MAS)
- Multiple endocrine neoplasia type 1 (MEN-1)
If excess growth hormone occurs after normal bone growth has stopped, the condition is known as acromegaly.
Gigantism is very rare.
The child will grow in height, as well as in the muscles and organs. This excessive growth makes the child extremely large for his or her age.
Other symptoms include:
- Delayed puberty
- Double vision or difficulty with side (peripheral) vision
- Frontal bossing and a prominent jaw
- Gaps between the teeth
- Increased sweating
- Irregular periods (menstruation)
- Large hands and feet with thick fingers and toes
- Release of breast milk
- Sleep problems
- Thickening of the facial features
Exams and Tests
The doctor will perform a physical exam and ask about the child's symptoms.
Laboratory tests that may be ordered include:
- Estradiol (girls)
- Growth hormone suppression test
- Increased growth factor-I
- Testosterone (boys)
- Thyroid hormone
For pituitary tumors with well-defined borders, surgery can cure many cases.
When surgery cannot completely remove the tumor, medicines are used to block or reduce growth hormone release.
Pituitary surgery is usually successful in limiting growth hormone production.
Early treatment can reverse many of the changes caused by growth hormone excess.
Surgery may lead to low levels of other pituitary hormones, which can cause:
When to Contact a Medical Professional
Call your health care provider if your child has signs of excessive growth.
Melmed S, Kleinberg D. Pituitary masses and tumors. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa: Elsevier Saunders; 2011: chap 9.
Last reviewed 11/7/2013 by Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.
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