Context: Although pituitary tumors are common, pituitary carcinoma is very rare and is only diagnosed when pituitary tumor noncontiguous with the sellar region is demonstrated. Diagnosis is difficult, resulting in delays that may adversely effect outcome that is traditionally poor. Barriers to earlier diagnosis and management strategies for pituitary carcinoma are discussed. Evidence Acquisition: PubMed was employed to identify relevant studies, a review of the literature was conducted, and data were summarized and integrated from the author's perspective. Evidence Synthesis: The available data highlight the difficulties in diagnosis and management and practical challenges in conducting clinical trials in this rare condition. They suggest that earlier diagnosis with aggressive multimodal therapy may be advantageous in some cases. Conclusions: Although pituitary carcinoma remains difficult to diagnose and treat, recent developments have led to improved outcomes in selected cases. With broader use of molecular markers, efforts to modify current histopathological criteria for pituitary carcinoma diagnosis may now be possible. This would assist earlier diagnosis and, in combination with targeted therapies, potentially improve long-term survival.

Context Cushing disease, a chronic hypercortisolism disorder, is associated with considerable morbidity and mortality. Normalizing cortisol production is the primary treatment goal. Objective We aimed to evaluate the safety and efficacy of osilodrostat, a potent, orally available 11βhydroxylase inhibitor, compared with placebo in patients with Cushing disease. Methods LINC 4 was a phase III, multicenter trial comprising an initial 12-week, randomized, double-blind, placebo-controlled (osilodrostat:placebo, 2:1) period followed by a 36-week, open-label treatment period (NCT02697734). Adult patients (aged 18-75 years) with confirmed Cushing disease and mean urinary free cortisol (mUFC) excretion ≥ 1.3 times the upper limit of normal (ULN) were eligible. The primary endpoint was the proportion of randomized patients with mUFC ≤ ULN at week 12. The key secondary endpoint was the proportion achieving mUFC ≤ ULN at week 36 (after 24 weeks’ open-label osilodrostat). Results Seventy-three patients (median age, 39 years [range, 19-67]; mean/median mUFC, 3.1 × ULN/2.5 × ULN) received randomized treatment with osilodrostat (n = 48) or placebo (n = 25). At week 12, significantly more osilodrostat (77%) than placebo (8%) patients achieved mUFC ≤ ULN (odds ratio 43.4; 95% CI 7.1, 343.2; P < 0.0001). Response was maintained at week 36, when 81% (95% CI 69.9, 89.1) of all patients achieved mUFC ≤ ULN. The most common adverse events during the placebo-controlled period (osilodrostat vs placebo) were decreased appetite (37.5% vs 16.0%), arthralgia (35.4% vs 8.0%), and nausea (31.3% vs 12.0%). Conclusion Osilodrostat rapidly normalized mUFC excretion in most patients with Cushing disease and maintained this effect throughout the study. The safety profile was favorable.

Context Aggressive prolactin-secreting pituitary adenomas that are resistant to conventional therapy with dopamine agonists, surgery, and radiation pose a therapeutic challenge. The mTOR inhibitor everolimus is approved to treat neuroendocrine tumors (NETs) and co-treatment with the somatostatin receptor ligand octreotide improved median progression free survival in patients with metastatic pancreatic NETs. Case Description We describe off-label everolimus treatment of a prolactinoma (PRLoma) refractory to cabergoline, repeat surgical resection and radiation therapy. Addition of everolimus to cabergoline led to decreased prolactin levels and tumor regression after 5 months. Tumor size remained stable for 12 months, and although prolactin levels rose, they remained below pretreatment levels. Immunohistochemical (IHC) evaluation of expression of key mTOR pathway drivers of cell proliferation revealed elevated p-AKT, p-4EBP1 and p-S6 in the index patient’s tumor. IHC analysis of 7 additional PRLomas demonstrated increased expression of nuclear p-AKT, cytoplasmic p-S6 and globally increased p-4EBP1 in the PRLomas compared to 11 autopsy-derived normal pituitary tissues. In in vitro studies in murine mammosomatotroph tumor GH3 cells, we observed that both the dopamine agonist cabergoline and the mTOR inhibitor everolimus inhibited GH3 cell proliferation and PRL secretion as single agents, and synergistic effect was noted with combination treatment only on inhibition of PRL secretion but not proliferation. Conclusions In summary, our findings demonstrate that the mTOR pathway is activated in PRLomas and everolimus exhibits anti-proliferative actions in vitro. We suggest that everolimus may be a novel therapeutic option for some aggressive PRL-secreting tumors unresponsive to conventional treatments.

Pituitary tumours, originating from endocrine cells of the anterior pituitary, are quite common, and in most cases well-controlled by surgery or medical treatment. However, a small subset of pituitary tumours presents with multiple local recurrences or tumour progression despite combined surgical, medical or radiotherapeutic treatment. These are known as aggressive pituitary tumours (APT); also called aggressive pituitary neuroendocrine tumours (PitNETs); or, in the rare case of metastases, pituitary carcinomas (PC) or metastatic PitNETs. Early identification of APT is challenging but is of major clinical importance as they are associated with an increased morbidity and mortality even in the absence of metastases. Here, we provide a revision of the first international, interdisciplinary European Society of Endocrinology (ESE) clinical practice guideline on APTs and PC (2018). Since publication of the 2018 guideline, results from the second ESE survey on APT and PC were published, and more data on APT treatment, including temozolomide, immune checkpoint inhibitors and bevacizumab, emerged. These data are reviewed in this guideline and translated into a practical algorithm to guide APT and PC management. Furthermore, standardized reporting of imaging and histopathological investigations of these tumours is proposed, and the role of molecular analysis is discussed. Last, a section is dedicated to special circumstances such as APT in pregnancy.

Adipose tissue is an important metabolic organ that is crucial for whole-body insulin sensitivity and energy homeostasis. Highly refined fructose intake increases visceral adiposity although the mechanism(s) remain unclear. Differentiation of preadipocytes to mature adipocytes is a highly regulated process that is associated with characteristic sequential changes in adipocyte gene expression. We demonstrate that fructose treatment of murine 3T3-L1 cells incubated in standard differentiation medium increases adipogenesis and adipocyte-related gene expression. We further show that the key fructose transporter, GluT5, is expressed in early-stage adipocyte differentiation but is not expressed in mature adipocytes. GluT5 overexpression or knockdown increased and decreased adipocyte differentiation, respectively, and treatment of 3T3-L1 cells with a specific GluT5 inhibitor decreased adipocyte differentiation. Epidymal white adipose tissue was reduced in GluT5−/− mice compared with wild-type mice, and mouse embryonic fibroblasts derived from GluT5−/− mice exhibited impaired adipocyte differentiation. Taken together, these results demonstrate that fructose and GluT5 play an important role in regulating adipose differentiation.