Hypopituitarism in patients with prolactinomas: a narrative review

Pituitary adenomas are the most frequent cause of hypopituitarism in adults, due to the mass effect of the lesion on the pituitary gland, and/or their treatments (particularly surgery and/or radiotherapy). Prolactinomas represent the most frequent histotype of hormone-secreting pituitary adenomas. As is well known, high prolactin levels induce a suppression of the gonadotropic axis and subsequent hypogonadotropic hypogonadism. Overall, the reported prevalence of hypopituitarism is highly heterogeneous in the different studies, depending on the definition used and the cohort examined. Treatment of prolactinomas, whether medical or surgical, can lead to improvement or recovery of pituitary function in a substantial proportion of patients, particularly of the gonadal axis. Conversely, new pituitary deficits can also develop after surgical treatment or, more frequently, radiotherapy. In this review, we aim to summarize the currently available literature data on hypopituitarism in patients with prolactinoma, in order to better characterize patients requiring replacement therapy.