GH/PRL-secreting pituitary macroadenoma associated with GNAS p.Gln227Leu mutation: pediatric case report and review

: GH-secreting pituitary adenomas (GHomas) are rare in the pediatric population. Guanine nucleotide-binding protein, alpha stimulating (GNAS) somatic mutations are often found in patients with GHoma. Here, we report an 8-year-old girl with GH-secreting pituitary adenoma successfully treated by operative tumor resection and postoperative treatment with octreotide long-acting release (LAR). Tumor DNA sequence analysis revealed a somatic heterozygous c.680A>T (p.Gln227Leu) mutation in GNAS. We reviewed 1,084 cases of GHomas, 409 (37.7%) of which harbored GNAS mutations. In pediatrics cases, aged 15 years or younger, 11 harbored a GNAS mutation, and GNAS p.Arg201Cys was identified in five cases. No other cases of codon 227 mutation were detected. These cases suggest that, in pediatric patients, the clinical features of GHoma may differ from those observed in adults. This is possibly related to octreotide or dopamine agonist resistance. Of six patients with surgical resistance, only one was reactive when treated with octreotide. Our case shows that octreotide LAR is an effective choice for treating GNAS-induced GHoma. This is the first report detailing the effectiveness of octreotide LAR in a GNAS codon 227 mutation-induced GHoma in a pediatric case. Examination of the relationship between genetic variation and clinical features in pediatric patients will enable us to assess the long-term effects of surgical and medical treatment of GHomas.