Case of the Month: Pediatric ESAP

esap 2017

This issue highlights Pediatric Endocrine Self-Assessment Program. Test your clinical knowledge and prepare for your exam. Available on the online store.


Clinical Vignette

A 6-and-a-half-year-old boy presents for evaluation of short stature. He was growing along the 5th percentile until age 4 years. His birth history is unremarkable. His parents are of low-normal stature with a midparental target height of 65.4 in (166 cm) (–1.40 SDS, 8th percentile).

On physical examination, his weight is 37.5 lb (17 kg) (–2.08 SDS), height is 41.7 in (106 cm) (–2.42 SDS), and lower segment is 16.5 in (42 cm). The upper-to-lower segment ratio is 1.5. There is no evidence of scoliosis. Pubic hair is Tanner stage 1, and testicles are 2 mL in volume. Acanthosis nigricans is present on the neck. Hair and nails are normal.

Laboratory test results:

  • IGF-1 = 159 ng/dL (20.8 nmol/L) (reference range, 38-253 ng/dL [5.0-33.1 nmol/L])
  • Fasting glucose = 78 mg/dL (4.3 mmol/L) (reference range [fasting], 70-105 mg/dL [3.9-5.8 mmol/L])
  • Fasting insulin = 6 μIU/mL (41.6 pmol/L) (reference range [fasting], 0-17 μIU/mL [0-118.1 pmol/L])
  • Bone age is determined to be 6 years by the Greulich and Pyle method.

Which of the following is the most likely diagnosis?

  1. Achondroplasia
  2. Hypochondroplasia
  3. Acromesomelic dysplasia, Maroteaux type
  4. Cartilage-hair hypoplasia
  5. Rabson-Mendenhall syndrome