Does He Have Acromegaly or Something Similar?

Patient Presentation
A 14-year-old male came to clinic for his health supervision visit. He and his parents had no concerns other than his growth. “He’s already 6 feet like me and I’m having problems finding shoes to fit him,” stated his mother. He had always been taller (> 95%) with a medium build. He was doing well in school, played basketball and threw the discus and shot put in track. The past medical history showed no concerns The family history revealed that mother was 6 feet tall and went through puberty at 13 years, his father was 6 feet 6 inches and went through puberty “late” and was slow to go through it per his mother. Both parents stated they were average size for their families. Mother joked, “Our families always play forward on the basketball teams.” His younger brother was also > 95% for height. A maternal grandmother had a goiter at an older age, and a paternal uncle had some heart problem in his late 40’s. There was another paternal uncle who died in a car accident in his 40’s. The parents were of Germanic and Scandinavian heritage. The review of systems was negative and he denied any drug or supplement use.

The pertinent physical exam showed a height of 72 inches (> 95%), weight of 165 pounds (90-95%) with normal vital signs. HEENT demonstrated some mild facial and back closed comedomal acne. He had a normal thyroid gland and no frontal bossing, large chin, or facial edema. His heart examination was also normal with no abdominal bruits. Genitourinary examination showed a Tanner III male. Musculoskeletal examination found his upper segment proportional to his lower segment and his arm span was within 1/2 inch of his height. The diagnosis of a healthy male was made, but the physician was concerned that although his height concerns were most likely familial, perhaps he had acromegaly, Marfan syndrome or some other abnormality that should be identified. The patient was referred to endocrinology. The radiologic and laboratory evaluation produced a normal bone age, thyroid studies, IGF-1 and growth hormone levels in addition to a normal echocardiogram confirming the diagnosis of familial growth stature. The patient’s clinical course at age 18 showed his adult height to be 6 feet 7 inches. His brother was following a similar growth pattern also.

Discussion
Acromegaly is caused by abnormal growth hormone and IGF-1 (insulin-like growth factor 1) after the growth plates are closed. It is called gigantism if it occurs when the growth plates are open and causes increased linear growth. Acromegaly, since it acts on closed growth plates, shows other physical signs including frontal bossing, prognathism, coarse facial features, macrocephaly, moderate obesity, thickened skin, thickened fingers and toes, hyperhidrosis and other problems. If the IGF-1 exposure is prolonged other problems occur such as cardiac hypertrophy and osteoarthritis. Benign tumors are also relatively common with acromegaly, but increased risk of malignancies is controversial. Acromegaly usually occurs in the 3rd decade but gigantism can occur at any age prior to growth plate fusion and death is usually due to cardiac and respiratory problems.

IGF-1 excess can be caused by pituitary excess secretion, pituitary dysregulation or excess IGF binding protein which prolongs IGF half-life. If caused by pituitary excess secretion it is often a part of other endocrinopathies especially abnormal growth hormone, and increased prolactin. It can be seen as a part of other abnormalities including McCune-Albright syndrome, Tuberous Sclerosis, and Neurofibromatosis.

Acromegaly is usually diagnosed with an increase in IGF-1. Imaging of the pituitary is commonly done to look for adenomas or other pituitary abnormalities. Treatment may include surgery and hormone agonists (e.g. dopamine, somatostatin, etc.) and antagonists (e.g. growth hormone receptor).

Learning Point
The differential diagnosis of excessive height/length includes:

• Familial or constitutional (most common)
• Acromegaly or gigantism
• Beckwith-Wiedemann Syndrome (as infant)
• Congenital adrenal hyperplasia (untreated)
• Eosinophilic adenoma
• Homocystinuria
• Lipodystrophy
• Marfan’s syndrome
• Neurofibromatosis
• Soto syndrome
• Weaver’s syndrome
• Various genetic various of sex chromosomes
  • Fragile X
  • Kleinfelter’s syndrome
  • 47 XYY
  • 48 XXYY

A review of overgrowth syndromes can be found here.

Questions for Further Discussion
1. How successful is surgery for treatment of gigantism or acromegaly?
2. What is the differential diagnosis of short stature?

Related Cases

Disease: Growth Disorders

Symptom/Presentation: Growth Problems

Specialty: Endocrinology | General Pediatrics

Age: Teenager

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com, the National Guideline Clearinghouse and the Cochrane Database of Systematic Reviews.

Information prescriptions for patients can be found at MedlinePlus for this topic: Growth Disorders

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

Illingworth RS. Common Symptoms of Disease in Children. Blackwell Scientific Publications: Oxford. 1988:28-29.

Renehan AG, Brennan BM. Acromegaly, growth hormone and cancer risk. Best Pract Res Clin Endocrinol Metab. 2008 Aug;22(4):639-57.

Ferry RJ Jr, Kemp S. Gigantism and Acromegaly. Medscape.
Available from the Internet at http://emedicine.medscape.com/article/925446-workup (rev. 7/10/2010, cited 3/26/3012).

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