According to this classification, PitNETs are either functional (secreting) adenomas or Silent Pituitary Adenomas (SPAs), also called Non-functioning Pituitary Adenomas (NFPAs), which are non-secreting forms of pituitary adenomas, classified according to TF expression to silent PIT1, silent TPIT, silent SF1, or null cell tumors (5, 6). Here, SF1 is linked to pituitary gland adenoma.