[Functional Pituitary Adenoma/Neuroendocrine Tumors].

Recently, the therapeutic outcomes of most patients with functioning pituitary neuroendocrine tumors have significantly improved because of advanced surgical and medical treatments. Surgical progress is due to the evolution of endoscopic techniques, refinement of surgical instruments, and continued technical innovations. The primary therapeutic goal for functioning tumors is endocrine remission, and treatment should be implemented within a comprehensive therapeutic strategy, in which surgery is crucial. Endoscopic endonasal surgery is a microsurgical procedure and its success relies on securing an adequately wide surgical corridor while respecting the nasal cavity. In enclosed, non-invasive, functioning tumors, selective total resection should be pursued, with meticulous identification of the tumor-normal tissue interface, including extracapsular dissection, if feasible. Tumor invasion of the cavernous sinus remains the most significant independent predictor of unfavorable outcomes; however, in some cases, resection of the medial wall may offer a high likelihood of achieving remission. For large invasive tumors, surgery aims to achieve maximal safe debulking and tumor control along with adjuvant medical and/or radiation therapies.