SAT-308 Obsessive and Compulsive Behavioral Change during Combination Treatment of Aromatase Inhibitor and Recombinant Human Growth Hormone in Early Puberty Patient: A Case Report

Aromatase inhibitor (AI), mostly combined with recombinant human growth hormone (rhGH), has been proposed as a effective treatment to improve the final adult height in short pubertal boys by delaying growth plate closure. However, safety concerns also remain, because of limited safety profile of AI usage in pediatric population. Several recent studies have revealed adverse effects of AI, including possible alterations in vertebral bone growth and vertebral anomalies, decreased HDL, increased hematocrit. Although that estrogens might have a role in the regulations of cognitive functions and AIs that block estrogen synthesis cross the blood-brain barrier, a recent trial suggested that AI did not impact the cognitive performance in peripubertal boys. In this report, we would like to introduce a rare case of showing obsessive and compulsive behavioral change in a early pubertal boy who was co-treated with AI and rhGH. A 13 years and 5 months-old boy visited our clinic and his initial examination revealed as follows; height was 160.5cm (45th percentile) and weight was 47.6kg (29th percentile); secondary sexual characteristics of Tanner stage IV. His pelvis x-ray showed risser stage 2, which is assessed to be about 16 years of bone age. He was otherwise healty with no other medical problems. His father's height was 170cm, his mother's height was 151cm, and his midparental height was calculated as 167cm. The patient and his parents wanted to improve his final adult height, and we commenced combination treatment of AI and rhGH after taking agreement. We prescribed letrozole 2.5mg once a day. After 2 months of the start of AI treatment, his parents compaint of his obsessive and compulsive behavioral change, which was not noticed before taking the drug. He complaint of obsessive thoughts and unwanted emotional pull that caused anxiety and distress. Also, he showed compulsive behavior of repeating reading one phrases of the same page. He was in intense stressful situation of preparing important test, however, we could not rule out the possibility of potential adverse effect of AI. Therefore, we discontinued AI. After discontinuing the drug, the symptom improved. During 3 months of combination treatment, he has achieved his height as 162.4cm with a gain of 1.9cm. The progression of bone age was successfully suppressed during the treatment. In conclusion, no significant influence on cognitive performance has been reported in previous studies, however, those studies focused on memory function. Potential effects on other behavioral change have not heen extensively evaluated. Therefore, clinicicans should be aware of possibility of compulsive behavioral change in AI-treated early pubertal boys, and further studies are needed to reveal the relationship.