Pituitary-dependent Cushing disease

**Definition:** Pituitary-dependent Cushing disease is caused by a pituitary tumour, generally benign (adenoma) but rarely malignant (carcinoma), which secretes adrenocorticotropin (ACTH) autonomously, leading to hypercortisolism. The condition is associated with increased morbidity and mortality that can be mitigated by treatments that result in sustained endocrine remission. Transsphenoidal pituitary surgery (TSS) remains the mainstay of treatment for this disease but requires considerable neurosurgical expertise and experience in order to optimize patient outcomes.