Etiology and pathology of Cushing’s disease: The pathological types of Cushing’s disease include pituitary ACTH adenoma, pituitary ACTH cell hyperplasia, and failure to detect adenoma or hyperplasia, with the percentages of the above pathological types being 75.4%, 8.3%, and 16.3%, respectively. Diagnosis and differential diagnosis of Cushing’s disease: Cushing’s disease diagnosis depends on three diagnostic basis, including: ① typical signs and symptoms of Cushing’s syndrome, including full-moon face, buffalo back, acne, hirsutism, purple lines, osteoporosis and easily accompanied by morbidity and mortality fracture, some patients with hypertension and diabetes mellitus, hydroelectrolytic disorders, etc.; ② endocrine examination: cortisol level is increased with the disappearance of the rhythm, the ACTH level is normal or elevated, the LDDST is normal or elevated, the LDDST is normal or elevated, the LDDST is normal or elevated, and the LDDST is normal. Endocrine examination: elevated cortisol level with loss of rhythm, normal or elevated ACTH level, LDDST cannot be inhibited, HDDST can be inhibited; ③ MRI found pituitary adenoma. However, the complexity of the etiology of Cushing’s syndrome leads to difficulties in localizing and confirming the diagnosis in some patients. First of all, the clinical symptoms of the patient may be atypical, the clinical manifestation of only one or several signs and symptoms, and some patients with cyclic Cushing’s syndrome or subclinical Cushing’s disease in hormone levels in the trough period when the manifestation of hypercortisolism can not be obvious. Systematic endocrine screening is particularly important in patients presenting with Cushing’s syndrome.A high basal UFC value that is not suppressed by the LDDST test is considered to be Cushing’s syndrome, otherwise it is considered to be simple obesity, with a sensitivity of 94% and a specificity of 90%. The traditional dexamethasone suppression test has some limitations in the diagnosis of Cushing’s disease, not all patients with Cushing’s disease dexamethasone suppression test are consistent with the characteristics of the disease, there are still 21% of patients with high basal values or LDDST can be suppressed. In patients with Cushing’s syndrome who have endocrine atypia and in whom MRI fails to detect a pituitary adenoma, BIPSS is valuable in identifying the etiology of the disease, and is characterized by a high degree of safety, fewer complications, and a high degree of sensitivity and specificity. Cushing’s disease is predominantly characterized by microadenomas. In addition to Cushing’s disease with definite adenomas on MRI, 36-63% of patients with clinical symptoms and endocrine examination are consistent with Cushing’s disease but MRI is negative, and surgical exploration is still indicated in these patients. Dynamically enhanced MRI can increase the detection rate of microadenomas from 51.3% to 87.2% in patients with Cushing’s disease compared to normal enhanced MRI. Treatment of Cushing’s disease: Although there are various treatment options for pituitary ACTH adenomas, transsphenoidal pituitary microadenoma resection plus peritubercular pituitary resection is the safe and effective treatment of choice for Cushing’s disease. The indications for Cushing’s disease surgery in our department are: MRI clear pituitary adenoma and endocrine hormone tests consistent with Cushing’s disease. Relative indications for pituitary exploratory surgery are: negative MRI, multiple endocrine tests consistent with Cushing’s disease and exclusion of Ectopic ACTH syndrome and adrenal tumors. Factors affecting surgical efficacy include: tumor size, aggressiveness, nature of pathology, and degree of peritumoral pituitary resection. Complications of transsphenoidal surgery are mild, and common complications are urolithiasis, electrolyte disorders, palpitations, cerebrospinal fluid leakage, and hypopituitarism. Long-term postoperative follow-up is very important and has three main purposes: to decide the amount of hormone for replacement therapy based on the hormone level of the rechecked patients with hypopituitarism; to decide whether or not to perform pituitary radiotherapy or adrenalectomy for patients whose hormones have not decreased to normal levels after surgery; and to find out the recurrence of the tumor at an early stage and take countermeasures accordingly. The postoperative recurrence rate was 13.3%. The treatment of partially refractory Cushing’s disease is still a difficult problem in clinical treatment. For Cushing’s disease after transsphenoidal surgery to review the MRI for the vacuolar pterygoid saddle, no signs of residual tumor or recurrence, high cortisol symptoms signs do not relieve and again ruled out the EAS ectopic ACTH-secreting tumors or, or residual tumor is located in the cavernous sinus with invasion of the patient, can be used to first pituitary gamma knife treatment or ordinary radiotherapy, still can not control the cause of the disease, but patients with high cortisol status need urgent treatment, can be done first on one side of the Adrenalectomy and then contralateral major resection if necessary, but close follow-up of pituitary enhancement MRI and blood/urine cortisol and ACTH levels should be performed to find out whether the patient develops Nelson’s syndrome at an early stage.