The tale in evolution: clarity, consistency and consultation, not contradiction and confusion

Consensus guideline for the diagnosis and management of pituitary adenomas in childhood and adolescence: Part 1, general recommendations

Tumours of the anterior part of the pituitary gland represent just 1% of all childhood (aged <15 years) intracranial neoplasms, yet they can confer high morbidity and little evidence and guidance is in place for their management. Between 2014 and 2022, a multidisciplinary expert group systematically developed the first comprehensive clinical practice consensus guideline for children and young people under the age 19 years (hereafter referred to as CYP) presenting with a suspected pituitary adenoma to inform specialist care and improve health outcomes. Through robust literature searches and a Delphi consensus exercise with an international Delphi consensus panel of experts, the available scientific evidence and expert opinions were consolidated into 74 recommendations. Part 1 of this consensus guideline includes 17 pragmatic management recommendations related to clinical care, neuroimaging, visual assessment, histopathology, genetics, pituitary surgery and radiotherapy. While in many aspects the care for CYP is similar to that of adults, key differences exist, particularly in aetiology and presentation. CYP with suspected pituitary adenomas require careful clinical examination, appropriate hormonal work-up, dedicated pituitary imaging and visual assessment. Consideration should be given to the potential for syndromic disease and genetic assessment. Multidisciplinary discussion at both the local and national levels can be key for management. Surgery should be performed in specialist centres. The collection of outcome data on novel modalities of medical treatment, surgical intervention and radiotherapy is essential for optimal future treatment.

Primary Pituitary Carcinoids Do Not Exist: A Reappraisal in the Era of Pituitary Neuroendocrine Tumours

The World Health Organization classification of pituitary tumours, published in 2022, supported a change in the terminology from "pituitary adenoma" to "pituitary neuroendocrine tumour" (PitNET). The neuroendocrine cells represent an integral part of the diffuse neuroendocrine system, including, among others, thyroid C cells, the parathyroid chief cells, and the anterior pituitary. Normal and neoplastic adenohypophyseal neuroendocrine cells have light microscopic, ultrastructural features and an immunoprofile compatible with the neuroendocrine cells and neuroendocrine tumours from other organs. Moreover, neuroendocrine cells of pituitary origin express transcription factors which indicate their cell-lineage origin. Thus, pituitary tumours are now considered as a continuum with other neuroendocrine tumours. PitNETs may occasionally be aggressive. In this context, the term "pituitary carcinoid" has no specific meaning: it either represents a PitNET, or a metastasis to the pituitary gland of a neuroendocrine tumour (NET). An accurate pathological evaluation, combined where necessary with functional radionuclide imaging, can define the origin of the tumour. We recommend that clinicians liaise with patient groups to understand the terminology to define primary tumours of adenohypophyseal cells. It is incumbent upon the responsible clinician to explain the use of the word "tumour" in a given clinical context.

Aggressive pituitary tumors (PitNETs)

The majority of anterior pituitary tumors behave benignly, that is, they grow slowly and do not metastasize, and were therefore called adenomas. However, they would frequently invade adjacent structures, leading to recurrence. One of the misleading assumptions in their previous classification was the simplistic distinction made between adenoma and carcinoma. In the upcoming WHO 2022 classification, a new terminology will be introduced: pituitary neuroendocrine tumor (PitNET) which is consistent with that used for other neuroendocrine neoplasms. In general, aggressive PitNETs are invasive and proliferative tumors with frequent recurrences, resistant to conventional treatments, and yet virtually without metastases. At present, no single morphological or histological marker has been shown as yet to reliably predict their aggressive behavior. In terms of treatment, temozolomide (TMZ) had been considered promising and the sole therapeutic option for aggressive and malignant PitNETs following failure of standard therapies. However, recent reports have disclosed that TMZ does not provide long-term control of many aggressive PitNETs. A further multidisciplinary approach is necessary for both reliable prediction and successful management of aggressive PitNETs.

Clinical Biology of the Pituitary Adenoma

All endocrine glands are susceptible to neoplastic growth, yet the health consequences of these neoplasms differ between endocrine tissues. Pituitary neoplasms are highly prevalent and overwhelmingly benign, exhibiting a spectrum of diverse behaviors and impact on health. To understand the clinical biology of these common yet often innocuous neoplasms, we review pituitary physiology and adenoma epidemiology, pathophysiology, behavior, and clinical consequences. The anterior pituitary develops in response to a range of complex brain signals integrating with intrinsic ectodermal cell transcriptional events that together determine gland growth, cell type differentiation, and hormonal production, in turn maintaining optimal endocrine health. Pituitary adenomas occur in 10% of the population; however, the overwhelming majority remain harmless during life. Triggered by somatic or germline mutations, disease-causing adenomas manifest pathogenic mechanisms that disrupt intrapituitary signaling to promote benign cell proliferation associated with chromosomal instability. Cellular senescence acts as a mechanistic buffer protecting against malignant transformation, an extremely rare event. It is estimated that fewer than one-thousandth of all pituitary adenomas cause clinically significant disease. Adenomas variably and adversely affect morbidity and mortality depending on cell type, hormone secretory activity, and growth behavior. For most clinically apparent adenomas, multimodal therapy controlling hormone secretion and adenoma growth lead to improved quality of life and normalized mortality. The clinical biology of pituitary adenomas, and particularly their benign nature, stands in marked contrast to other tumors of the endocrine system, such as thyroid and neuroendocrine tumors.

Epigenetic and post-transcriptional regulation of somatostatin receptor subtype 5 (SST5 ) in pituitary and pancreatic neuroendocrine tumors

Somatostatin receptor subtype 5 (SST₅) is an emerging biomarker and actionable target in pituitary (PitNETs) and pancreatic (PanNETs) neuroendocrine tumors. Transcriptional and epigenetic regulation of SSTR5 gene expression and mRNA biogenesis is poorly understood. Recently, an overlapping natural antisense transcript, SSTR5‐AS1, potentially regulating SSTR5 expression, was identified. We aimed to elucidate whether epigenetic processes contribute to the regulation of SSTR5 expression in PitNETs (somatotropinomas) and PanNETs. We analyzed the SSTR5/SSTR5‐AS1 human locus in silico to identify CpG islands. SSTR5 and SSTR5‐AS1 expression was assessed by quantitative real‐time PCR (qPCR) in 27 somatotropinomas, 11 normal pituitaries (NPs), and 15 PanNETs/paired adjacent (control) samples. We evaluated methylation grade in four CpG islands in the SSTR5/SSTR5‐AS1 genes. Results revealed that SSTR5 and SSTR5‐AS1 were directly correlated in NP, somatotropinoma, and PanNET samples. Interestingly, selected CpG islands were differentially methylated in somatotropinomas compared with NPs. In PanNETs cell lines, SSTR5‐AS1 silencing downregulated SSTR5 expression, altered aggressiveness features, and influenced pasireotide response. These results provide evidence that SSTR5 expression in PitNETs and PanNETs can be epigenetically regulated by the SSTR5‐AS1 antisense transcript and, indirectly, by DNA methylation, which may thereby impact tumor behavior and treatment response.

Pituitary adenoma…nomen omen?

BACKGROUND

In 2017, the International Pituitary Pathology Club proposed to rename pituitary adenoma as pituitary neuroendocrine tumors (PitNETs) but since no consensus on this new terminology was obtained the Pituitary Society decided to host on this topic an international multidisciplinary virtual workshop, Pituitary Neoplasm Nomenclature (PANOMEN), to which several Societies participated with the designation of their representatives in the expert panel. Main conclusion of the meeting was that there was not yet a case for adopting the PitNET nomenclature and main recommendation was that the term adenoma is retained.

AIM

Aim of this Editorial is to comment the outcome of the recently published document of the meeting.

CONCLUSIONS

Ideally, only the combination of pathological, neuroradiological, and clinical data can define the degree of agressiveness/invasion of a pituitary adenoma and effectively guide treament. This may be classically obtained only with a close multisciplinary collaboration into a PTCOE. It is proposed that improved definition of "invasive" and "aggressive" neoplasms may represent the most clinically effective development in the clinico-neuroradiological-pathological denomination and classification of pituitary adenomas.

Classification of neuroendocrine neoplasms: lights and shadows

Neuroendocrine neoplasms (NENs) are a heterogeneous group of neoplastic proliferations showing different morphological features, immunophenotype, molecular background, clinical presentation, and outcome. They can virtually originate in every organ of the human body and their classification is not uniform among different sites. Indeed, as they have historically been classified according to the organ in which they primarily arise, the different nomenclature that has resulted have created some confusion among pathologists and clinicians. Although a uniform terminology to classify neuroendocrine neoplasms arising in different systems has recently been proposed by WHO/IARC, some issues remain unsolved or need to be clarified. In this review, we discuss the lights and shadows of the current WHO classifications used to define and characterize NENs of the pituitary gland, lung, breast and those of the head and neck region, and digestive and urogenital systems.

Pituitary adenoma or pituitary neuroendocrine tumor: a narrative review of controversy and perspective

In 1932, Harvey Cushing first proposed pituitary adenoma (PA) as the term for the cause of acromegaly. After nearly 90 years of research, PA is recognized as the second most common intracranial neoplasm. Most PAs can be easily cured or controlled by conventional therapies, including surgery, medical treatment or radiotherapy. However, nearly 40% of PAs are invasive, and some adenomas show aggressive behavior, with rapid growth patterns and resistance to conventional treatments, which leads to a poor prognosis; this type of adenoma is called aggressive or refractory PA. For a very small proportion of PAs (approximately 0.2%), subarachnoid or systemic metastasis may develop, at which point it is considered malignant and called pituitary carcinoma. Based on distinctions regarding the biological behaviors of adenoma, aggressive adenoma and pituitary carcinoma, the International Pituitary Pathology Club in 2016 formally proposed new terminology for PA: pituitary neuroendocrine tumor (PitNET). Over the last three years, an increasing number of relevant articles have used the term PitNET in place of PA. Interestingly, the fourth edition of the WHO classification of PA released in 2017 did not adopt this nomenclature, and the Pituitary Society published a paper in 2019 suggesting that the new nomenclature does not improve clinical diagnosis or treatment and confuses patients more than the PA terminology. The Pituitary Society insists on using the term PA, as PAs with aggressive behavior only account for a very small proportion of all PAs. Overall, the new terminology may cause significant and unnecessary patient anxiety and confusion. Here, we describe the current perspectives and bases of the two naming methods and offer our opinions on maintaining the original naming system for PA. Nevertheless, early diagnosis and intensive treatment of aggressive PAs is extremely important for improving patient prognosis, regardless of the nomenclature.

Genetics of Acromegaly and Gigantism

Growth hormone (GH)-secreting pituitary tumours represent the most genetically determined pituitary tumour type. This is true both for germline and somatic mutations. Germline mutations occur in several known genes (AIP, PRKAR1A, GPR101, GNAS, MEN1, CDKN1B, SDHx, MAX) as well as familial cases with currently unknown genes, while somatic mutations in GNAS are present in up to 40% of tumours. If the disease starts before the fusion of the epiphysis, then accelerated growth and increased final height, or gigantism, can develop, where a genetic background can be identified in half of the cases. Hereditary GH-secreting pituitary adenoma (PA) can manifest as isolated tumours, familial isolated pituitary adenoma (FIPA) including cases with AIP mutations or GPR101 duplications (X-linked acrogigantism, XLAG) or can be a part of systemic diseases like multiple endocrine neoplasia type 1 or type 4, McCune-Albright syndrome, Carney complex or phaeochromocytoma/paraganglioma-pituitary adenoma association. Family history and a search for associated syndromic manifestations can help to draw attention to genetic causes; many of these are now tested as part of gene panels. Identifying genetic mutations allows appropriate screening of associated comorbidities as well as finding affected family members before the clinical manifestation of the disease. This review focuses on germline and somatic mutations predisposing to acromegaly and gigantism.

Pituitary Neoplasm Nomenclature Workshop: Does Adenoma Stand the Test of Time?

The WHO Classification of Endocrine Tumours designates pituitary neoplasms as adenomas. A proposed nomenclature change to pituitary neuroendocrine tumors (PitNETs) has been met with concern by some stakeholder groups. The Pituitary Society coordinated the Pituitary Neoplasm Nomenclature (PANOMEN) workshop to address the topic. Experts in pituitary developmental biology, pathology, neurosurgery, endocrinology, and oncology, including representatives nominated by the Endocrine Society, European Society of Endocrinology, European Neuroendocrine Association, Growth Hormone Research Society, and International Society of Pituitary Surgeons. Clinical epidemiology, disease phenotype, management, and prognosis of pituitary adenomas differ from that of most NETs. The vast majority of pituitary adenomas are benign and do not adversely impact life expectancy. A nomenclature change to PitNET does not address the main challenge of prognostic prediction, assigns an uncertain malignancy designation to benign pituitary adenomas, and may adversely affect patients. Due to pandemic restrictions, the workshop was conducted virtually, with audiovisual lectures and written précis on each topic provided to all participants. Feedback was collated and summarized by Content Chairs and discussed during a virtual writing meeting moderated by Session Chairs, which yielded an evidence-based draft document sent to all participants for review and approval. There is not yet a case for adopting the PitNET nomenclature. The PANOMEN Workshop recommends that the term adenoma be retained and that the topic be revisited as new evidence on pituitary neoplasm biology emerges.

Best Achievements in Pituitary and Adrenal Diseases in 2020

Significant progress in pituitary and adrenal diseases was made in 2020. This review presents major translational and clinical advances in research on pituitary and adrenal diseases, encompassing their epidemiology, pathogenesis, diagnosis, and clinical management. We address the controversy regarding the nomenclature of pituitary neuroendocrine tumors, omics-based molecular classification of pituitary adenomas, and novel drugs for Cushing's disease in the field of pituitary diseases. In the field of adrenal diseases, we cover big data-driven epidemiology of adrenal tumors, steroid profiling as a new diagnostic tool, and the utility of scoring systems in the decision-making process of managing primary aldosteronism. This brief article will broaden readers' understanding of pituitary and adrenal diseases.

Novel Insights into Pituitary Tumorigenesis: Genetic and Epigenetic Mechanisms

Substantial advances have been made recently in the pathobiology of pituitary tumors. Similar to many other endocrine tumors, over the last few years we have recognized the role of germline and somatic mutations in a number of syndromic or nonsyndromic conditions with pituitary tumor predisposition. These include the identification of novel germline variants in patients with familial or simplex pituitary tumors and establishment of novel somatic variants identified through next generation sequencing. Advanced techniques have allowed the exploration of epigenetic mechanisms mediated through DNA methylation, histone modifications and noncoding RNAs, such as microRNA, long noncoding RNAs and circular RNAs. These mechanisms can influence tumor formation, growth, and invasion. While genetic and epigenetic mechanisms often disrupt similar pathways, such as cell cycle regulation, in pituitary tumors there is little overlap between genes altered by germline, somatic, and epigenetic mechanisms. The interplay between these complex mechanisms driving tumorigenesis are best studied in the emerging multiomics studies. Here, we summarize insights from the recent developments in the regulation of pituitary tumorigenesis.

Prospective Evaluation of Incidental Pituitary Imaging Findings in the Sella Turcica

Purpose

Reported rates of incidentally discovered pituitary sellar lesions vary widely, at least in part because of the inadvertent inclusion of patients with a history suspicious for a pituitary disorder. We prospectively evaluated the incidence of truly incidental sellar findings detected on imaging at a large academic medical center.

Methods

Deidentified data were extracted from the electronic medical record of adults who underwent diagnostic computed tomography (CT) or magnetic resonance imaging (MRI) over a 1-year period for any cause unrelated to known or suspected pituitary disorder both in inpatient and outpatient settings. Patients with International Classification of Diseases, Ninth Revision, (ICD-9) and Tenth Revision (ICD-10) codes indicative of a sellar lesion and those with symptoms suggestive of sellar/parasellar mass effects were excluded.

Results

Of 9572 scans performed during the 1-year study period, 3840 met the inclusion criteria to comprise the study cohort; 13 were manually excluded because of findings or symptoms of sellar masses not otherwise captured. The overwhelming majority of evaluable images (n = 3782) showed no sellar lesions. Truly incidental sellar findings were detected in 45 (1.2%), most commonly among inpatients (P < .001). Partially empty sella and empty sella were the most frequent findings, and were twice as likely to be detected on MRI vs CT. All other incidentally discovered lesions, including one microadenoma and one macroadenoma, were detected only by MRI.

Conclusion

Frequency of incidental sellar lesions in patients with no known or suspected history of pituitary disorder is low. Given the small likelihood of aggressive behavior in these lesions, the clinical significance of truly incidentally discovered sellar lesions should not be overestimated.