ESPE Abstracts

Background: Aromatase inhibitors (AI) are being used in clinical trials in children related to peripheral precocious puberty, and idiopathic short stature to improve height prognosis.

Case report: A 2 ^11/12 year-old boy was referred to our center for evaluation of penile enlargement and pubic hair development. Physical examination revealed a well-developed muscular boy with a body weight of 22 kg (>97p), height of 110.1 cm (>97p), with oily skin and acnea on his face. His blood pressure was 140/90 mmHg. Testicular volumes were 6 cc, stretched penile length was 9 cm and he had Tanner stage II pubic hair. His bone age was 13 years with predicted adult height of 129.5 cm. Laboratory results with total testosterone: 10.01 nmol//l, ACTH: 1250 mmol/l, 17-OH progesteron: 5.75 nmol/l, Plasma renin activity: 0.1 μg/l per hour, 11-desoxycortisol: 140 ng/ml were consistent with 11-β hydroxylase deficiency. Genetic analysis demonstrated a previously described g.4643_4644insGA mutation in CYP11β1. After 9 months of initiation of hydrocortisone treatment, his bone age became 13 6/12 years, which gave him an adult height predicton of 130 cm. Because of this poor height prognosis, patient was started on letrozole 2.5 mg/day, After 11 years of letrozole therapy, at the age of 15 y 5/12 mo his near-final height is 157.7 cm, bone age is 14 y 9/12 mo and predicted adult height is 164.4 cm. The expense to this dramatic increase in height prognosis is a decrease in bone mineral density (DEXA) Z-score from −0.3 to −0.9 during treatment with some morphologic changes in vertebral bodies noted on MRI.

Conclusion: As far as we know, this is the longest duration of letrozole use to improve height potential and is highly encouraging regarding the use of aromatase inhibitors early in the disease course in selected patients with advanced bone-age and severely impaired height prognosis.