Related Experiment Videos
Acromegaly in an infant
D L Blumberg1, C A Sklar, R David
1Department of Pediatrics, New York University Medical Center, NY 10016.
Insights
This study reports on the youngest known case of acromegaly in a child with a growth hormone-secreting pituitary adenoma. Post-surgery, hyperprolactinemia may have sustained normal growth by stimulating somatomedin C.
Area of Science:
- Pediatric Endocrinology
- Neuroendocrinology
- Oncology
Background:
- Growth hormone-secreting pituitary adenomas are rare in children.
- Acromegaly, caused by excess growth hormone, typically presents later in life.
- Hyperprolactinemia can coexist with growth hormone-secreting tumors.
Observation:
- A 21-month-old girl presented with macrocephaly and rapid growth, diagnosed with acromegaly.
- Preoperative hormone levels showed significantly elevated growth hormone, somatomedin C, and prolactin.
- Tumor resection revealed a growth hormone-secreting adenoma without prolactin production.
Findings:
- Postoperatively, growth hormone levels normalized, and growth velocity returned to normal.
- Somatomedin C levels normalized, while prolactin remained moderately elevated.
- Sustained normal growth post-surgery suggests hyperprolactinemia's role in stimulating somatomedin C.
Implications:
- This case highlights the youngest documented instance of childhood acromegaly.
- It suggests a potential role for hyperprolactinemia in maintaining growth despite low growth hormone post-treatment.
- Further research is needed to understand the interplay between growth hormone, prolactin, and somatomedin C in pediatric growth disorders.
Abstract:
Serial hormonal studies were carried out in a girl with a growth hormone-secreting pituitary adenoma and hyperprolactinemia diagnosed at 21 months of age, the youngest verified case of acromegaly. The child had progressive macrocephaly, noted at 6 months of age, which preceded the rapid acceleration of linear growth by nearly 1 year. At 21 months of age, the girl's head circumference measured 55 cm (+5.5 SD) and her height was 97.6 cm (+4.4 SD). Preoperative serum growth hormone level was 135 ng/mL, somatomedin C was 1,540 ng/mL (normal for bone age 18 to 97 ng/mL), and prolactin was 370 ng/mL (normal less than 20 ng/mL). Following total resection of a large adenoma, immunohistochemical staining of the tumor showed growth hormone but not prolactin. With longitudinal monitoring of the child for 2 years postoperatively, persistently low growth hormone levels were demonstrated and normal growth velocity (6 cm/yr). Peak serum growth hormone levels ranged from 2.8 to 4.1 ng/mL after stimulation tests with insulin, arginine, and L-dopa. Maximum sleep-entrained growth hormone level was 3.4 ng/mL. At the same time, serum somatomedin C levels measured serially were normal (29 to 111 ng/mL), whereas simultaneous prolactin levels were moderately increased (30 to 147 ng/mL). The data support the hypothesis that hyperprolactinemia may have contributed to stimulating somatomedin C and sustaining the normal growth rate in this child.