IntroductionProlactinomas are the most frequent type of pituitary adenoma encountered in clinical practice. Dopamine agonists (DA) like cabergoline typically provide sign/ symptom control, normalize prolactin levels and decrease tumor size in most patients. DA-resistant prolactinomas are infrequent and can occur in association with some genetic causes like MEN1 and pathogenic germline variants in the AIP gene (AIPvar).MethodsWe compared the clinical, radiological, and therapeutic characteristics of AIPvar-related prolactinomas (n=13) with unselected hospital-treated prolactinomas (“unselected”, n=41) and genetically-negative, DA-resistant prolactinomas (DA-resistant, n=39).ResultsAIPvar-related prolactinomas occurred at a significantly younger age than the unselected or DA-resistant prolactinomas (p50%) occurred in 58.3% in the AIPvar group versus 4.2% in the DA-resistant group (p