What Is Gigantism?

Gigantism is a rare condition that occurs in children when there is an overproduction of the growth hormone (GH) before the onset of puberty. The pituitary gland is responsible for making the growth hormone, called somatotropin. When there is an excessive amount of growth hormones in the body, a child will usually grow much taller than other children their age. A child with gigantism will also have accelerated muscle and organ growth.

There are two types of gigantism: childhood gigantism and adult gigantism (acromegaly). Gigantism is a treatable condition, and the earlier you treat it, the greater the chances of managing its effects on the body. Treatments aim to manage pituitary tumor growth and control the GH levels.

How Rare Is Gigantism?

Gigantism is an extremely rare condition. This rarity makes early diagnosis and treatment crucial to manage the condition effectively.

What Triggers Gigantism?

Gigantism is usually triggered or caused by a noncancerous tumor on the pituitary gland. When a tumor develops on the pituitary gland, the gland makes more growth hormones than is necessary. Some other less common causes of gigantism include:

• McCune-Albright syndrome: This syndrome causes abnormal growth in bone tissue, gland abnormalities, and patches of light brown skin.
• Carney complex: This inherited condition causes noncancerous tumors to grow on the connective tissue, noncancerous or cancerous endocrine tumors, and patches of darker skin.
• Multiple endocrine neoplasia type 1 (MEN1): This inherited condition causes tumors in the pituitary gland, pancreas, or parathyroid glands.
• Neurofibromatosis: This inherited condition causes tumors to develop in the nervous system.

Symptoms

There are several symptoms of gigantism. The most common symptom your child may exhibit is being much taller than children their own age. Other symptoms include:

• Elevated levels of growth hormone (GH)
• Large hands and feet
• Thicker fingers and toes
• Enlarged or prominent jaw and forehead
• Larger nose, lips, and tongue
• Gaps between teeth
• Excessive sweating
• Accelerated muscle and organ growth
• Early bone maturation
• Premature growth of pubic hair
• Delayed onset of menstruation

Diagnosing

Doctors use several different methods for diagnosing gigantism. The most common methods of diagnosing are through a physical exam, blood tests, and imaging tests.

• Physical exam: During the exam, your doctor will gather a thorough medical history, ask about symptoms, and recommend any necessary blood tests or imaging tests if gigantism is suspected.
• Blood tests: Blood tests will consist of checking for high levels of GH (GH and IGF-1 tests) and determining whether there is the presence of a pituitary tumor through an oral glucose tolerance test (OGTT).
• Imaging tests: These types of tests are used to detect a pituitary tumor, or to determine bone age. Imaging tests that are typically used are MRI scans, CT scans, and bone age X-rays.

Treatment

Treatment of gigantism looks to correct and manage four main areas: pituitary tumor growth, the effects of the tumor on surrounding nerve and brain structures, the reduction and management of elevated levels of GH, and the systemic consequences of elevated GH.

The most effective treatment options include:

• Surgery: If the underlying cause of gigantism is a tumor, the most preferred treatment option is having surgery to remove the tumor.
• Radiation therapy: This type of treatment is used to destroy the cancer cells and prevent their growth. Radiation therapy may be recommended if it is determined that surgery is not possible.
• Medication: This treatment is used to control the production of GH or to limit the systemic effects it has on the body.

Long-Term Management of Gigantism

Long-term management of gigantism is important, specifically if you were unable to have surgery to remove the tumor. Regular monitoring to keep GH levels under control is important. Additionally, long-term management may be required if gigantism was treated later in life and there are ongoing systemic effects on the body. Long-term effects on the bones, joints, and heart are common.

If you or your child are experiencing symptoms of gigantism, find a local endocrinologist today!