Large-scale second-hit AIP deletion causing a pediatric growth hormone-secreting pituitary adenoma: Case report and review of literature.

Gigantism (early-onset acromegaly) is a rare pediatric disorder caused by a growth hormone (GH)-secreting pituitary adenoma. Approximately 50% patients of gigantism have a germline mutation, most commonly an inactivating mutation in the aryl-hydrocarbon interacting receptor protein (AIP) gene on chromosome 11q13.2. We present an 11-year-old male patient with a GH-secreting pituitary macroadenoma who presented with excessive growth spurts, behavioral changes, and frontal headaches. He was successfully treated with an endoscopic endonasal gross total resection and subsequently demonstrated biochemical cure. Whole-exome sequencing showed a heterozygous germline mutation in the AIP gene suggesting pituitary adenoma predisposition. Analysis of the tumor tissue revealed a large-scale deletion on chromosome 11 overlapping with AIP leading to bi-allelic AIP loss. Coincident germline and somatic AIP mutations were likely causal in formation of a GH-secreting adenoma with an aggressive phenotype. This case exemplifies the need for early diagnosis and curative surgery in the management of AIP-mutated pituitary adenomas.