POMC and adenoma: Based on the clinical manifestations, PAs are categorized into non-functional PAs and functional PAs (FPAs) which include growth hormone (GH)-secreting adenoma (GHPA), prolactinoma, thyrotropin (TSH)-secreting adenoma, and corticotropin (ACTH)-secreting adenoma (Tjörnstrand and Nyström, 2017).