Coordinated Health


Gigantism is abnormal growth due to an excess of growth hormone during childhood.

Alternative Names

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)
  • Neurofibromatosis

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
  • Headache
  • 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
  • Weakness

Exams and Tests

The doctor will perform a physical exam and ask about the child’s symptoms.

Laboratory tests that may be ordered include:

  • Cortisol
  • Estradiol (girls)
  • Growth hormone suppression test
  • Prolactin
  • Increased growth factor-I
  • Testosterone (boys)
  • Thyroid hormone

Imaging tests, such as CT or MRI scan of the head, also may be ordered to check for a pituitary tumor.


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.

Outlook (Prognosis)

Pituitary surgery is usually successful in limiting growth hormone production.

Early treatment can reverse many of the changes caused by growth hormone excess.

Possible Complications

Surgery may lead to low levels of other pituitary hormones, which can cause:

  • Adrenal insufficiency
  • Diabetes insipidus (rarely)
  • Hypogonadism
  • Hypothyroidism

When to Contact a Medical Professional

Call your health care provider if your child has signs of excessive growth.