As the pituitary adenoma continues to increase in diameter to 2-4 mm, the compressed pituitary gland surrounding the tumor forms an envelope-like structure that separates the tumor from the surrounding normal pituitary gland. The pituitary adenoma pseudo-envelope is formed by the compressed pituitary vesicles and their surrounding reticular fibers, and contains collagen III. The pituitary adenoma pseudopapillary contains more reticular fibers, is tough and has a light yellow color. The tougher pituitary adenoma pseudo-envelope was visible after careful separation of the thin surface layer of pituitary tissue during surgery. The tumor is separated by scraping along the border between the pituitary adenoma pseudo-envelope and the pituitary tissue. Most of the pituitary microadenomas can be removed completely. For large pituitary adenoma, intracapsular resection can be done first, followed by extracapsular resection along the pituitary adenoma pseudo-envelope after decompression. If the tumor grows upward, it may adhere tightly to the saddle diaphragm and arachnoid membrane, so care should be taken to peel off the pituitary adenoma pseudo-envelope and protect the saddle diaphragm arachnoid membrane as much as possible. If intraoperative cerebrospinal fluid leakage is found, autologous fascia, muscle and bone pieces should be taken for repair.