GH1 and adenoma: They arise from the pituitary in the sella turcica and are classified as either clinically non-functioning pituitary adenomas (NFPAs) or clinically functioning adenomas such as prolactinomas (PRL), adrenocorticotropic hormone (ACTH)-secreting, growth hormone (GH)-secreting or thyroid-stimulating hormone (TSH)-secreting adenomas3.