The goal of this clinical trial is to assess the need for hydrocortisone replacement therapy during the perioperative period for large pituitary neuroendocrine tumors. The main questions it aims to answer are:

• Does hydrocortisone replacement therapy reduce the incidence of adrenal insufficiency in participants? Researchers will compare hydrocortisone to a placebo (a look-alike substance that contains no drug) to see if hydrocortisone works to reduce the incidence of adrenal insufficiency.

Participants will:

• Take or intravenous infusion drug hydrocortisone or a placebo every day for 2 weeks
• Visit the clinic three months after surgery for checkups and tests
• Keep a diary of their symptoms

Inclusion Criteria:

• (1) Age range: 18-70 years old;
• (2) Accept PitNETs patients who can be treated with endoscopic transsphenoidal surgery;
• (3) The maximum diameter of the tumor is ≥ 2 centimeters;
• (4) Preoperative hypothalamic pituitary adrenal axis integrity;
• (5) The subject or their legal representative signs the informed consent form

Exclusion Criteria:

• (1) Patients with a history of Cushing's disease or adrenal insufficiency;
• (2) Emergency and combined hormone therapy patients;
• (3) Pituitary stroke patients;
• (4) Patients lacking head magnetic resonance imaging;

Research data involves subject privacy