Prolactinomas are the most frequent type of pituitary tumors, which represent 10–20% of all intracranial neoplasms in humans. Prolactinomas develop in mice lacking the prolactin receptor (PRLR), which is a member of the cytokine receptor superfamily that signals via Janus kinase-2-signal transducer and activator of transcription-5 (JAK2-STAT5) or phosphoinositide 3-kinase-Akt (PI3K-Akt) pathways to mediate changes in transcription, differentiation and proliferation. To elucidate the role of the PRLR gene in human prolactinomas, we determined the PRLR sequence in 50 DNA samples (35 leucocytes, 15 tumors) from 46 prolactinoma patients (59% males, 41% females). This identified six germline PRLR variants, which comprised four rare variants (Gly57Ser, Glu376Gln, Arg453Trp and Asn492Ile) and two low-frequency variants (Ile76Val, Ile146Leu), but no somatic variants. The rare variants, Glu376Gln and Asn492Ile, which were in complete linkage disequilibrium, and are located in the PRLR intracellular domain, occurred with significantly higher frequencies (P < 0.0001) in prolactinoma patients than in 60 706 individuals of the Exome Aggregation Consortium cohort and 7045 individuals of the Oxford Biobank. In vitro analysis of the PRLR variants demonstrated that the Asn492Ile variant, but not Glu376Gln, when compared to wild-type (WT) PRLR, increased prolactin-induced pAkt signaling (>1.3-fold, P < 0.02) and proliferation (1.4-fold, P < 0.02), but did not affect pSTAT5 signaling. Treatment of cells with an Akt1/2 inhibitor or everolimus, which acts on the Akt pathway, reduced Asn492Ile signaling and proliferation to WT levels. Thus, our results identify an association between a gain-of-function PRLR variant and prolactinomas and reveal a new etiology and potential therapeutic approach for these neoplasms.

Cancer immunotherapy has introduced a novel class of drugs known as immune checkpoint inhibitors (ICIs). They enhance antitumour immunity by blocking negative regulators (checkpoints) of T cell function that exist on both immune and tumour cells. ICIs targeting CTLA-4 and PD-1/PDL-1 have dramatically changed the outcome of patients with several advanced-stage malignancies but they may lead to a variety of inflammatory toxicities and autoimmune consequences. The main endocrine immune-related adverse events (IRAEs) include hypophysitis, primary thyroid dysfunction, adrenalitis and type 1 diabetes mellitus. In general, the management of endocrine IRAEs requires assessment of their severity, in moderate or severe cases interruption of the checkpoint inhibitor and use of corticosteroid or alternative immunosuppression and appropriate hormone replacement or treatment when necessary.

Functioning gonadotroph adenomas (FGAs) are rare tumors, as the overwhelming majority of gonadotroph tumors are clinically silent. Literature is based on case reports and small case series. Gonadotroph tumors are poorly differentiated and produce and secrete hormones inefficiently, but in exceptional cases, they cause clinical syndromes due to hypersecretion of intact gonadotropins. The clinical spectrum of endocrine dysfunction includes an exaggerated response of ovaries characterized as ovarian hyperstimulation syndrome (OHSS) in premenopausal females and adolescent girls, testicular enlargement in males, and isosexual precocious puberty in children. Transsphenoidal surgery and removal of tumor reduces hormonal hypersecretion, improves endocrine dysfunction, and provides tissue for further analysis. Medical therapies (somatostatin analogues, dopamine agonists, GnRH agonists/antagonists) are partially or totally ineffective in many cases, especially with respect to antitumor effect. This review aims to update recent literature on these rare functioning tumors and highlight their therapeutic management.

Cardiovascular comorbidities owing to hormonal excess or deficiency are the main cause of mortality in patients with pituitary disorders. In patients with Cushing’s Disease, there is an increased prevalence of cardiovascular diseases and/or risk factors including visceral obesity, insulin resistance, atherosclerosis, arterial hypertension, dyslipidaemia, hypercoagulability as well as structural and functional changes in the heart, like cardiac hypertrophy and left ventricle (LV) dysfunction. Notably, these demonstrate limited reversibility even after remission. Furthermore, patients with acromegaly may manifest insulin resistance but also structural and functional heart changes, also known as “acromegalic cardiomyopathy”. Patients with prolactinomas demonstrate an aggravation of metabolic parameters, obesity, dysregulation of glucose and lipid metabolism as well as endothelial dysfunction. Hypopituitarism and conventional hormonal replacement therapy may also contribute to an unhealthy metabolic status, which promotes atherosclerosis and may lead to premature mortality. This review discusses the literature on cardiovascular risk in patients with pituitary disorders to increase physician awareness regarding this aspect of management in patients with pituitary disorders.

Pituitary adenomas (PAs) are common intracranial tumors. Despite their benign nature, PAs may cause a significant burden of disease, leading to either hormonal disturbances or local compression. A subset of PAs presents an aggressive behavior that remains difficult to predict, and in rare cases they metastasize. Therefore, early diagnosis and treatment are important. Advances in molecular pathology have improved the understanding of their pathogenesis and offer opportunities to identify and target novel pathways. Improved imaging and functional molecular techniques precisely detect even very small tumors and guide targeted treatment. Transsphenoidal surgery is the first-line treatment for the majority of PAs, and advances in the field of endoscopic neurosurgery offer excellent outcomes. Dopamine agonists (DAs) are traditionally the first-line treatment for prolactinomas. For patients with acromegaly, first- and second-generation somatostatin analogues (SSAs) are applied when surgery is not successful or not indicated. For Cushing’s disease (CD), drugs targeting adrenal steroidogenesis, somatostatin receptors in the pituitary, and glucocorticoid receptors are used to treat hypercortisolism in patients with persistent or recurrent CD, for those who are not good surgical candidates, and as a bridge treatment for those who have undergone radiation treatment until cortisol levels are controlled. Temozolomide (TMZ) is the first-line chemotherapy for aggressive PAs, but new experimental therapies, like the anti-vascular endothelial growth factor (anti-VEGF) therapy, mechanistic target of rapamycin (mTOR) inhibitors, tyrosine kinase inhibitors, and cell cycle and checkpoint inhibitors, are now available. Radiotherapy is offered to patients with residual, recurrent, or progressive tumors. Modern techniques in radiotherapy planning and delivery are able to deliver high doses to the target tissue while sparing vital structures. As we familiarize ourselves with the biological behavior of PAs and our therapeutic armamentarium expands, the next goal is to tailor and personalize treatment to each individual patient so as to achieve the best outcome.