Patients with AIP mutations have macroadenomas in up to 90% of the cases, and their tumours are significantly larger and more frequently show an extrasellar extension compared with non-mutated familial8 and sporadic cases.6–8 Cases of double adenomas have also been described among AIP mutation positive patients,32 while pituitary hyperplasia associated with GH excess33 34 is rare. This evidence concerns the gene AIP and neoplasm.