AIP and multiple endocrine neoplasia: ACTH-secreting adenomas due to germline mutations can rarely arise in the context of familial disorders, such as multiple endocrine neoplasia type 1 (MEN1), familial isolated pituitary adenomas (associated with aryl-hydrocarbon receptor-interacting protein [gene AIP] mutations), and MEN4 (associated with cyclin-dependent kinase inhibitors) (Dworakowska and Grossman 2012; Perez-Rivas and Reincke 2016).