A macroprolactinoma becoming resistant to cabergoline and developing atypical pathology

Abstract

The development of secondary resistance to dopamine agonists (DAs) is a serious sign as it may be associated with de-differentiation of the prolactinoma and thus of aggressive or malignant transformation.Significant de-differentiation of the adenoma documented on consecutive histologies suggests a possible transition to malignancy.A combination of histological 'alarm' features associated with persistent growth and escape from DAs treatment in recurrent adenomas should alert clinicians and demands close follow-up.A multidisciplinary approach by pathologists, endocrinologists and neurosurgeons is essential.