Acromegaly and Gigantism: Differences

1. Onset

Gigantism begins in childhood, whereas acromegaly starts between ages  20-40.

2. Causes

A pituitary tumor is the primary cause of both acromegaly and gigantism. However, other genetic conditions can also cause gigantism, including:

• Carney complex
• McCune-Albright syndrome
• Multiple endocrine neoplasia (type I or IV)
• Neurofibromatosis
• GPR101 gene mutation

Acromegaly can also be caused by tumors originating in areas of the body other than the pituitary gland, including:

• Lungs
• Pancreas
• Hypothalamus
• Adrenal glands
• Chest or abdomen

3. Main symptoms

Gigantism is characterized by the overall growth of the body to a ginormous proportion:

• Large hands and feet
• Thick toes and fingers
• Very soft hands
• Enlarged jaw and forehead
• Significant underbite
• Enlarged tongue, nose, and lips
• Deepening voice in boys
• Oily skin
• Excessive sweating
• Skin tags
• Joint pain
• Headache
• Difficulty sleeping
• Irregular menstrual periods

Acromegaly is characterized by the growth of only the acral parts (extremities):

• Enlarged hands and feet
• Misalignment of the teeth
• Enlarged lips, tongue, or jaw
• Deeper voice
• Muscle weakness
• Inability to sleep
• Fatigue
• Headaches
• Joint inflammation and pain, especially in large joints
• Curved spine
• Thickened or darkened skin
• Oily skin
• Excessive sweating
• Difficulty breathing
• Irregular heartbeat
• Excessive body hair
• Skin tags
• Spaces between the teeth
• Splayed fingers and toes
• Vision difficulties

4. Puberty

Women having acromegaly have regular puberty, as it starts around ages 20-40, but girls with gigantism may have delayed puberty.

5. Symptom progression

Symptoms progress rapidly in gigantism, whereas in acromegaly, the progression is slow.

6. Diagnosis

Acromegaly can be diagnosed with a simple blood test. In gigantism, the diagnosis is made with an X-ray or a CT scan.

7. Mortality rate

People who have acromegaly have a higher mortality rate than the general population. The mortality rate for gigantism is unknown. 

8. Complications

Complications associated with acromegaly include:

• High blood pressure
• Diabetes
• Sleep apnea
• Heart disease
• Hypopituitarism
• Arthritis
• Uterine fibroids
• Colon polyps
• Vision issues
• Compressed spinal cord
• Structural heart defects 

Complications associated with gigantism include:

• High blood pressure
• Diabetes
• Heart disease
• Heart failure due to an enlarged heart
• Thyroid cancer
• Hypothyroidism
• Colon polyps
• Hypopituitarism (or the low secretion of pituitary hormones)
• Delayed puberty

Treatment for both gigantism and acromegaly includes suppressing the production of growth hormones. Removing the pituitary tumor is the primary means of hormone suppression. Treatment options include:

Surgery

Removal of the pituitary tumor is the first line of treatment. All or parts of the tumor may be removed to prevent the release of growth hormone. Minimal invasive surgery is recommended if the tumor is accessible and medium-sized. 

Medications

Medications are advised in the following scenarios:

• Surgery is not possible
• No suppression of growth hormones even after surgery
• Shrinkage of a large tumor before surgery

Commonly used medications include:

• Somatostatin analog
• Dopamine agonists
• Growth hormone receptor antagonists

Radiation therapy

Radiation therapy helps shrink and destroy the tumor with the help of beam radiation. Options for radiation therapy include:

• Stereotactic irradiation: Involves administering one high dose of radiation to the tumor while preserving the surrounding tissues
• External irradiation: Involves administering smaller doses of radiation over several years at a frequency of every 4-6 weeks