The 2017 World Health Organization classification of tumors of the pituitary gland: a summary

Analysis of whole genome-wide microRNA transcriptome profiling in invasive pituitary adenomas and non-invasive pituitary adenomas

Background

Dysregulation of microRNAs (miRNAs) plays a critical role during the occurrence and progress of pituitary adenomas (PAs). However, the roles of miRNAs in the invasiveness of PA are poorly understood. This study aims to more comprehensively and specific define the relationship between altered miRNA and PA invasion.

Methods

The differential expression of miRNAs (DEMs) between invasive PAs (IPAs) and non-invasive PAs (NPAs) was explored by RNA sequencing and which functions were analyzed by gene ontology (GO) as well as Kyoto Encyclopedia of Genes and Genomes (KEGG). The miRNA-mRNA network was predicted with bioinformatics.

Results

We identified 31 upregulated miRNAs and 24 downregulated miRNAs in IPAs compared with NPAs. GO analysis and KEGG pathway analysis showed the DEMs were mainly associated with cell proliferation and cell cycle pathway. In addition, on the count of predicted miRNA-mRNA network, two hub miRNAs were identified.

Conclusions

Our results demonstrate the miRNA-mRNA network in detail, which suggest that miRNA may be a promising target in diagnosis and therapy for IPAs.

Surgical resection of granular cell tumor of the sellar region: three indications

PURPOSE

This case series evaluates the surgical management of granular cell tumor (GCT) of the sellar region. This rare entity presents a unique diagnostic and surgical challenge.

METHODS

Institutional neuropathology databases at Brigham and Women's Hospital and Massachusetts General Hospital were searched for cases with a tissue diagnosis of GCT, and with a location in the sellar region. Patient, treatment, tumor, and follow-up data were extracted.

RESULTS

Three patients had a diagnosis of GCT of the sellar region occurring over an 18-year period. All three patients were followed postoperatively at our multidisciplinary pituitary center (median follow-up = 30 months; range 12-30 months). Hormonal disturbances, an incidental lesion requiring diagnosis, and neurological symptoms were indications for surgery in these patients. Two patients underwent a craniotomy and one underwent endoscopic transsphenoidal surgery. All three patients were free of tumor recurrence at last follow-up. In one case tested, positive thyroid transcription factor-1 (TTF-1) immunohistochemistry was observed.

CONCLUSION

GCT is generally a benign tumor of the sellar region. Surgical resection is the standard treatment, more recently with transsphenoidal surgery when indicated. Surgical resection results in optimal outcome for patients.

Predicting the likelihood of early recurrence based on mRNA sequencing of pituitary adenomas

Background

There is no comprehensive and objective method existing for predicting early recurrence of pituitary adenomas (PAs). The most advanced gene sequencing technology can be applied to build a prognostic model that can effectively predict early recurrence of PAs.

Methods

In this study, using mRNA-Seq data, the corresponding postoperative early recurrence status, and other clinical features of 107 PA samples were obtained and randomly divided into the training and validation groups. Cox regression and receiver operating characteristic (ROC) analysis accompanied by the risk score method was used to build a seven-gene prediction model.

Results

Area under curve values was 0.857 in the training group, 0.936 in the validation group, and 0.848 in all patients. Patients with low-risk scores had a significantly lower probability of early postoperative recurrence compared to those acquiring high-risk scores in the training group, validation group, and all patient (P<0.0001) groups. In addition, 6 out of these 7 significant genes were highly correlated to the early recurrence of PAs.

Conclusions

This prediction model derived from mRNA-Seq data may help in identifying the early recurrence of PAs, consequently aiding in the classification of patients with PAs and the administration of the appropriate therapeutic and follow-up strategy for these patients.

Endoscopic surgical treatment of Cushing's disease: A single-center experience of cauterization of peritumoral tissues

Endoscopic transsphenoidal surgery is a form of treatment for Cushing's disease that is initially preferred compared with other types of treatment. Peritumoral tissue is inactivated by cauterization if a clear border of the lesion cannot be identified. In order to compare the surgical outcomes and post-operative complications between patients who underwent inactivation (cauterization of peritumoral tissues is referred to as inactivation) and those who did not, the medical records of patients treated between January 2010 and June 2016 were retrospectively reviewed. Furthermore, the results of conventional examinations performed in order to diagnose and locate the tumors, including neuroimaging, high-dose dexamethasone suppression tests and/or bilateral inferior petrosal sinus sampling, were collected. A total of 79 consecutive patients with Cushing's disease were included in the present analysis. Inactivation of peritumoral tissue had been applied in 35 (44.3%) of the cases. A gross total resection was achieved in 73 (92.4%) of the cases, while partial resection had been performed in the remaining six (7.6%). Early post-operative endocrinological remission was attained in 71 (89.8%) of the patients. A total of seven cases suffered from hypopituitarism, while cerebrospinal fluid rhinorrhea and brain stem infarction were recorded in four cases and one case, respectively. During the follow-up, the duration of which ranged between 11 and 62 months, recurrence was documented in five patients, as determined by endocrinal examinations. All of the cases that were initially treated unsuccessfully and those with recurrence achieved endocrinological remission following radiotherapy. Enhanced pituitary magnetic resonance imaging revealed no further enlargement of tumors during follow-up. The extent of endocrinological remission, recurrence and post-operative complications did not significantly differ between patients who underwent inactivation and those who did not. In conclusion, inactivation of peritumoral tissue by cauterization achieved satisfactory results in patients with intricate lesions, however it is comparable to conventional procedures.

[Neuroendocrine tumors : Classification, clinical presentation and imaging]

CONTEXT

Neuroendocrine tumors (NET) are a heterogeneous group of neoplasms found in all organs. They often present with characteristic clinical syndromes due to hormone hypersecretion.

DIAGNOSTICS

In addition to hormone diagnostics molecular-genetic work-up can play an important role.

IMAGING

Morphological imaging comprises ultrasound, endoscopy, computed tomography (CT) and magnetic resonance imaging (MRI) scans. Functional imaging of NET relies on radioligands that bind to specific receptors or transporters (Ga-68-DOTATATE-PET-CT, Tc-99-tektrotyd-SPECT/CT, F‑18-DOPA-PET/CT).

THERAPY

Somatostatin analogs either native or coupled to radionuclides are potent drugs for treating various neuroendocrine tumors.

CONCLUSION

The requirements of imaging are determined by clinical presentation, laboratory findings, tumor stage, the presence of a tumor syndrome and the need of a personalized systemic treatment modality.

Spontaneous Pituitary Adenomas in Squirrel Monkeys (Saimiri sciureus)

On postmortem examination, 2 geriatric captive male squirrel monkeys (Saimiri sciureus) were found to have pituitary masses that were unassociated with previous experimental manipulation. Both animals were euthanized due to apparently unrelated clinical reasons. Histopathology and immunohistochemical staining classified these tumors as thyrotrophic and corticotrophic pituitary adenomas. These cases represent the first reports of this tumor type in squirrel monkeys.

Spindle cell oncocytoma of the pituitary gland

OBJECTIVE

The authors report the diagnosis, management, and outcomes of 6 cases of spindle cell oncocytoma (SCO) in an effort to guide clinical diagnosis and management of these uncommon lesions.

METHODS

This study is a retrospective review of cases involving adult patients who underwent resection of pituitary lesions at the authors' institutions between January 2000 and October 2017. The authors identified patients with histopathological confirmation of SCO and collected clinical data, including preoperative, perioperative, and postoperative management, complications, and outcomes.

RESULTS

Six patients with SCO were identified. Clinical findings at initial presentation included visual disturbances, dizziness, and headache. All patients underwent resection. Four resections were initially performed by the transsphenoidal approach, and 2 resections were performed by craniotomy at an outside institution with subsequent transsphenoidal reoperations. Neither necrosis nor increased mitotic activity was seen in the tumor samples. All samples stained positive for S100 protein and thyroid transcription factor 1 and negative for glial fibrillary acidic protein and pituitary hormones. Five of the samples stained positive for epithelial membrane antigen. The average MIB-1 index was 8.3% (range 2-17). Postoperatively, 3 of the 6 patients received further treatment for progression of residual tumor or for recurrence, 2 have stable residual tumor, and 1 has had no recurrence after gross-total resection. Two patients developed postoperative complications of transient sixth cranial nerve palsy and diplopia. There were no other complications.

CONCLUSIONS

SCO poses both a diagnostic and therapeutic challenge. These tumors are often initially misdiagnosed as nonfunctional pituitary adenomas because of their sellar location and nonspecific symptomatology. Postoperatively, SCO must also be distinguished from other neoplasms of the posterior pituitary gland through histopathological examination. Resection of SCO can be challenging, given its highly vascular and adherent nature. Long-term follow-up is critical, as the tumor is associated with higher recurrence and progression rates compared to other benign neoplasms of the sella.

Surgical management of clinically silent thyrotropin pituitary adenomas: A single center series of 20 patients

Silent thyrotropin pituitary adenomas (TSHomas) are defined by absence of hyperthyroidism despite TSH immunopositivity. Data pertaining to clinical and surgical characteristics of silent TSHomas remains limited. We aim to describe the clinical presentation, pathological characteristics, and outcomes in silent TSHoma patients treated at a tertiary pituitary center. We retrospectively identified patients with histologically-proven silent TSHoma who underwent transsphenoidal resection at our center between 2000 and 2016 (n = 1244 total patients). Patients with preoperative hyperthyroidism or thyroidectomy were excluded. Twenty patients with silent TSHomas were included (1.6% of surgically treated PAs), of which 35% were reoperations. Presenting symptoms included vision loss (45%) and headache (40%). Preoperative pituitary dysfunction included hypothyroidism (40%), hypogonadotropic hypogonadism (30%), and panhypopituitarism (15%). Nineteen patients (95%) had macroadenomas (mean diameter 29.9 mm). Extrasellar growth was identified in 17 patients (85%) and 65% had cavernous sinus invasion. Immunostaining for alpha-subunit was positive in 19 patients (95%), and 75% of tumors expressed immunopositivity for hormones other than TSH. Gross total tumor resection was achieved in 9 patients (45%) on follow-up MRI. Major postoperative complications included hydrocephalus (1 patient) and cerebrospinal fluid leak with meningitis (1 patient). Tumor progression and recurrence occurred in 1 patient each (10% total) over the follow-up period (median 18.5 months). Silent TSHomas tend to be large, invasive tumors. In addition to TSH, a majority express immunopositivity for alpha-subunit and gonadotropins, thereby potentially supporting a primitive adenoma lineage and subtype. Despite reoperation in several patients, good overall outcomes with low complication rates were achieved.

Acromegaly in the elderly patient

Acromegaly is an insidious disease, usually resulting from growth hormone hypersecretion by a pituitary adenoma. It is most often diagnosed during the 3rd to 4th decade of life. However, recent studies have shown an increase in the incidence and prevalence of acromegaly in the elderly, probably due to increasing life expectancy. As in the younger population with acromegaly, there is a delay in diagnosis, aggravated by the similarities of the aging process with some of the characteristics of the disease. As can be expected elderly patients with acromegaly have a higher prevalence of comorbidities than younger ones. The diagnostic criteria are the same as for younger patients. Surgical treatment of the pituitary adenoma is the primary therapy of choice unless contraindicated. Somatostatin receptor ligands are generally effective as both primary and postoperative treatment. The prognosis correlates inversely with the patient's age, disease duration and last GH level. Arch Endocrinol Metab. 2019;63(6):638-45.

Mammosomatotroph and mixed somatotroph-lactotroph adenoma in acromegaly: a retrospective study with long-term follow-up

PURPOSE

Although well-documented from pathological aspect, the clinical features and outcomes of acromegaly with mammosomatotroph (MSA) and mixed somatotroph-lactotroph adenoma (MSLA) are seldom reported. Thus, in this study, we analyzed and reported the clinical data about MSAs and MSLAs.

METHODS

We retrospectively reviewed medical records of patients with acromegaly in our institution during 2008-2017. Growth hormone (GH)-secreting adenomas were categorized into pure somatotroph adenoma (PSA), MSA and MSLA based on inclusion and exclusion criteria. Clinical information and treatment outcomes during follow-up were analyzed by univariate and multivariate methods.

RESULTS

Among 94 patients within this cohort, PSAs, MSAs, and MSLAs accounted for 53, 28 and 13 cases, respectively. MSAs often had smaller size, lower frequency of cavernous sinus invasion and higher gross total resection (GTR) rate. MSLAs were characterized by bigger tumor size, higher frequency of preoperative hyperprolactinemia, and lower GTR rate. Thus, MSLAs had worse long-term biological remission rate than MSAs and PSAs (15.4% vs. 50.0% and 26.4%, p = 0.0371). Gender (male, OR = 0.784, p = 0.011) and tumor volume (OR = 0.784, p = 0.020) were independent predictors for long-term biological remission in binary logistic regression. Subgroup analyses indicated that postoperative nadir GH level (GH-7, HR = 1.242, p = 0.001) was the only risk factor for tumor recurrence for patients with GTR.

CONCLUSIONS

Our results provide valuable insights into clinicopathological features of acromegaly. MSAs were relatively smaller lesions with better prognosis. MSLAs were more aggressive with massive size, invasiveness and preoperative hyperprolactinemia. Tumor size and GH-7 were significantly associated with biological remission and tumor relapse after GTR, respectively.

Hemangioblastoma arising from duramater: Case report

RATIONALE

Hemangioblastoma (HB) is a benign tumor that is typically located in the subtentorial region of the brain. HB that originates from dura mater is extremely rare.

PATIENT CONCERNS

Herein, we reported a single case of a patient who presented with dizziness and headache lasting for 1 year that progressively aggravated within 1 month.

DIAGNOSIS

After admission, the patient underwent head magnetic resonance (MR); a nodular long T1-T2 signal was found on the right side of parietal falx cerebri; the lesion appeared with high intensity on FLAIR and DWI, and with isointensity on ADC map. In addition, significant homogeneous enhancements were observed on the enhanced scan. According to clinical and imaging features, the lesion was diagnosed as meningioma. However, after performing tumor resection by craniotomy, the diagnosis of HB is clear. Additional pathological examination data were found: Ki-67(+1%), NSE(-), CD31(+), CD34(+), CD56(+), S-100(-), α-inhibin(+), Vimentin(-), EGFR-), GFAP(-), CK-pan(-), EMA(-), PR(-).

INTERVENTIONS

The mass with abundant blood supply was removed.

OUTCOMES

Ten days after operation, the patient was discharged from hospital and no signs of recurrence were observed three months later.

LESSONS

To sum up, obvious high signal intensity in T2WI sequence and homogeneous enhancement are main characteristics that differentiate dural hemangioblastoma from meningioma lesion.

Mitochondrial Dysfunction Pathway Networks and Mitochondrial Dynamics in the Pathogenesis of Pituitary Adenomas

Mitochondrion is a multi-functional organelle, which is associated with various signaling pathway networks, including energy metabolism, oxidative stress, cell apoptosis, cell cycles, autophagy, and immunity process. Mitochondrial proteins have been discovered to modulate these signaling pathway networks, and multiple biological behaviors to adapt to various internal environments or signaling events of human pathogenesis. Accordingly, mitochondrial dysfunction that alters the bioenergetic and biosynthetic state might contribute to multiple diseases, including cell transformation and tumor. Multiomics studies have revealed that mitochondrial dysfunction, oxidative stress, and cell cycle dysregulation signaling pathways operate in human pituitary adenomas, which suggest mitochondria play critical roles in pituitary adenomas. Some drugs targeting mitochondria are found as a therapeutic strategy for pituitary adenomas, including melatonin, melatonin inhibitors, temozolomide, pyrimethamine, 18 beta-glycyrrhetinic acid, gossypol acetate, Yougui pill, T-2 toxin, grifolic acid, cyclosporine A, dopamine agonists, and paeoniflorin. This article reviews the latest experimental evidence and potential biological roles of mitochondrial dysfunction and mitochondrial dynamics in pituitary adenoma progression, potential molecular mechanisms between mitochondria and pituitary adenoma progression, and current status and perspectives of mitochondria-based biomarkers and targeted drugs for effective management of pituitary adenomas.

Clinical, pathologic, and imaging characteristics of pituitary null cell adenomas as defined according to the 2017 World Health Organization criteria: a case series from two pituitary centers

PURPOSE

The 2017 World Health Organization classification of pituitary tumors redefined pituitary null cell adenomas (NCAs) by restricting this diagnostic category to pituitary tumors that are negative for pituitary transcription factors and adenohypophyseal hormones. The clinical behavior of this redefined entity has not been widely studied, and this is a major shortcoming of the classification. This study evaluated the imaging and clinical features of NCAs from two pituitary centers and compared them with those of gonadotroph adenomas (GAs).

METHODS

Imaging, pathologic, and clinical characteristics of NCAs and GAs were retrospectively reviewed. Tumor immunohistochemistry was performed to confirm absence of adenohypophyseal hormones and pituitary transcription factor expression.

RESULTS

Thirty-one NCAs were compared with 38 GAs. NCAs were more likely to invade the cavernous sinus (15/31 [48%] vs. 5/38 [13%], P = .003) and had a higher proliferative index (i.e., MIB-1 > 3%, 11/31 [35%] vs. 5/38 [13%], P = .04). Gross total resection was less likely in the NCA group (19/31 [61%] vs. 33/38 [87], P = .02). Progression-free survival was worse in the NCA cohort (5-year progression-free survival, 0.70 vs. 1.00; P = .011, by log-rank test).

CONCLUSIONS

Compared with GAs, NCAs are more invasive at the time of presentation and have a more aggressive clinical course. This study provides evidence that NCAs represent a distinct clinicopathologic entity with behavior that differs adversely from that of GAs. This may inform clinical decision-making, including frequency of postoperative tumor surveillance and timing of adjunctive treatments.

Regulating the CCNB1 gene can affect cell proliferation and apoptosis in pituitary adenomas and activate epithelial-to-mesenchymal transition

The aim of the present study was to investigate the role and potential regulatory mechanisms of cyclin B1 (CCNB1) in the proliferation, apoptosis and epithelial-to-mesenchymal transition (EMT) in pituitary adenomas. A total of 24 specimens were included in the present study. The expression levels of CCNB1 protein in two normal pituitary and 22 pituitary adenoma tissues were determined by western blotting. CCNB1 was knocked-down by lentiviral-mediated infection of short hairpin RNA (shRNA) in GH3 and MMQ cell lines. The proliferation, cell cycle and apoptosis of GH3 and MMQ cell lines were detected using a Cell Counting Kit-8 and flow cytometer. Reverse transcription-quantitative PCR was utilized to detect the expression level of CCNB1 gene and EMT markers. In the present study, resveratrol (RES) was used as an inhibitor of CCNB1. The protein expression level of CCNB1 in pituitary adenomas was higher than that in normal pituitary tissue, as assessed by western blot analysis. In addition, the expression level of CCNB1 in invasive pituitary adenomas was higher when comparing invasive pituitary adenomas and non-invasive pituitary adenomas. Knockdown of CCNB1 resulted in significant decreases in cell viability and proliferation, arrested cell cycle at the G₂/M phase and increased apoptosis. In addition, knockdown of CCNB1 significantly decreased the expression levels of the mesothelial cell marker N-cadherin (P<0.001), but significantly increased the expression levels of the epithelial cell markers E-cadherin (P<0.01) and p120-catenin (P<0.001). Further analyses identified that RES inhibited the expression level of CCNB1, and RES treatment exhibited a similar effect as CCNB1 shRNA infection. The present study suggested that suppressing the expression level of CCNB1 could regulate the proliferation and apoptosis of pituitary tumor cells and alter the expression level of various EMT markers. In addition, RES treatment could be used as an inhibitor of CCNB1. The present study also identified the molecular mechanisms underlying CCNB1 role in EMT.

Endothelial cell-specific molecule-1 as an invasiveness marker for pituitary null cell adenoma

BACKGROUND

Endothelial cell-specific molecule-1 (ESM-1) is a biomarker associated with tumor progression in pituitary adenoma. We specifically focused on one type of pituitary adenoma, namely null cell adenoma (NCA) and evaluated the relationship between invasion and ESM-1 expression in both vascular endothelial and adenoma tissues.

METHODS

Tissue samples from 94 patients with pituitary NCA were obtained through microscopic transsphenoidal resection. Tumor size and invasion were determined through preoperative magnetic resonance imaging. Immunohistochemical staining was performed to detect ESM-1 expression. ESM-1 index of ≥3 was defined as high expression.

RESULTS

Signs of invasion were observed in 46 (47.9%) of the 94 patients. Significant differences were observed in the invasion state and maximum tumor diameter between high and low expression of ESM-1 in vascular endothelial tissues (both P < 0.05). Significant positive associations were noted between ESM-1 expression in vascular endothelial tissues and tumor invasion (P = 0.002) and tumor size (P = 0.020). However, only tumor size was associated with ESM-1 expression in adenoma tissues (P = 0.016).

CONCLUSION

In NCA, a significant positive association between tumor invasion and ESM-1 expression was observed only in vascular endothelial tissues, suggesting that tumor progression occurs mainly through ESM-1-associated mechanism.

Management of Nonfunctioning Recurrent Pituitary Adenomas

Pituitary adenomas are typically slow-growing benign tumors. However, 50% to 60% of tumors progress following subtotal resection and up to 30% recur after apparent complete resection. Options for treatment of recurrent pituitary adenomas include repeat surgical resection, radiation therapy, and systemic therapies. There is no consensus approach for the management of recurrent pituitary adenomas. This article reviews the natural history of recurrent adenomas and emerging biomarkers predictive of clinical behavior as well as the outcomes associated with the various treatment modalities for these challenging tumors, with an emphasis on the surgical treatment.

Practical Application of Lineage-Specific Immunohistochemistry Markers: Transcription Factors (Sometimes) Behaving Badly

CONTEXT.—

Transcription factors (TFs) are proteins that regulate gene expression and control RNA transcription from DNA. Lineage-specific TFs have increasingly been used by pathologists to determine tumor lineage, especially in the setting of metastatic tumors of unknown primary, among other uses. With experience gathered from its daily application and increasing pitfalls reported from immunohistochemical studies, these often-touted highly specific TFs are not as reliable as once thought.

OBJECTIVES.—

To summarize the established roles of many of the commonly used TFs in clinical practice and to discuss known and potential sources for error (eg, false-positivity from cross-reactivity, aberrant, and overlap "lineage-specific" expression) in their application and interpretation.

DATA SOURCES.—

Literature review and the authors' personal practice experience were used. Several examples selected from the University Health Network (Toronto, Ontario, Canada) are illustrated.

CONCLUSIONS.—

The application of TF diagnostic immunohistochemistry has enabled pathologists to better assess the lineage/origin of primary and metastatic tumors. However, the awareness of potential pitfalls is essential to avoid misdiagnosis.

Molecular pathology of tumors of the central nervous system

Since the update of the 4th edition of the WHO Classification of Central Nervous System (CNS) Tumors published in 2016, particular molecular characteristics are part of the definition of a subset of these neoplasms. This combined 'histo-molecular' approach allows for a much more precise diagnosis of especially diffuse gliomas and embryonal CNS tumors. This review provides an update of the most important diagnostic and prognostic markers for state-of-the-art diagnosis of primary CNS tumors. Defining molecular markers for diffuse gliomas are IDH1/IDH2 mutations, 1p/19q codeletion and mutations in histone H3 genes. Medulloblastomas, the most frequent embryonal CNS tumors, are divided into four molecularly defined groups according to the WHO 2016 Classification: wingless/integrated (WNT) signaling pathway activated, sonic hedgehog (SHH) signaling pathway activated and tumor protein p53 gene (TP53)-mutant, SHH-activated and TP53-wildtype, and non-WNT/non-SHH-activated. Molecular characteristics are also important for the diagnosis of several other CNS tumors, such as RELA fusion-positive subtype of ependymoma, atypical teratoid rhabdoid tumor (AT/RT), embryonal tumor with multilayered rosettes, and solitary fibrous tumor/hemangiopericytoma. Immunohistochemistry is a helpful alternative for further molecular characterization of several of these tumors. Additionally, genome-wide methylation profiling is a very promising new tool in CNS tumor diagnostics. Much progress has thus been made by translating the most relevant molecular knowledge into a more precise clinical diagnosis of CNS tumors. Hopefully, this will enable more specific and more effective therapeutic approaches for the patients suffering from these tumors.

Invited Review: Pathology of pituitary neuroendocrine tumours: present status, modern diagnostic approach, controversies and future perspectives from a neuropathological and clinical standpoint

Neuroendocrine tumours of the adenohypophysis have traditionally been designated as pituitary adenomas to underline their usually indolent growth and lack of metastatic potential. However, they may demonstrate a huge spectrum of growth patterns and endocrine disturbances, some of them significantly affecting health and quality of life. To predict tumour growth, risk of postoperative recurrence and response to medical therapy in patients with pituitary neuroendocrine tumours is challenging. A thorough histopathological and immunohistochemical diagnostic work-up is an obligatory part of a multidisciplinary effort to precisely define the tumour type and assess prognostic and predictive factors on an individual basis. In this review, we have summarized the current status in the pathology in pituitary neuroendocrine tumours based on the selection of references from the PubMed database. We have presented possible diagnostic approaches according to the current pituitary cell lineage-based classification. The importance of recognizing histological subtypes with potentially aggressive behaviour and identification of prognostic and predictive tissue biomarkers have been highlighted. Controversies related to particular subtypes of pituitary tumours and a still limited prognostic impact of the current classification indicate the need for further refinement. Multidisciplinary approach including clinical, pathological and molecular genetic characterization will be essential for improved personalized therapy and the search for novel therapeutic targets in patients with pituitary neuroendocrine tumours.

The long non-coding RNA SNHG1 promotes glioma progression by competitively binding to miR-194 to regulate PHLDA1 expression

Long non-coding RNAs (lncRNAs) play a vital role in tumourigenesis, including that of glioma. Small nucleolar RNA host gene 1 (SNHG1) is a relatively novel lncRNA that is involved in the development of multiple human tumours. However, its underlying molecular mechanism in glioma has not been completely clarified. In this study, we show that SNHG1 is overexpressed in glioma tissues and cell lines. A series of functional assays suggested that SNHG1 promotes glioma progression in vitro and in vivo. Next, through online databases, a luciferase reporter assay and an RNA pull-down assay, we confirmed that SNHG1 functions as a sponge for miR-194, which acts as a suppressor in glioma. We also verified that pleckstrin homology like domain family A, member 1 (PHLDA1) is the functional target of miR-194. Moreover, rescue experiments demonstrated that SNHG1 regulates PHLDA1 expression in a miR-194-dependent manner. Taken together, our study shows that SNHG1 promotes glioma progression by competitively binding to miR-194 to regulate PHLDA1 expression, which may provide a novel therapeutic strategy for glioma.

Co-expression Network Analysis Elucidated a Core Module in Association With Prognosis of Non-functioning Non-invasive Human Pituitary Adenoma

Non-functioning pituitary adenomas (NFPAs) are tumors with clinically challenging features since they have insidious progression. A complex network of gene interactions is thought to have roles in tumor formation and progression. Therefore, revealing the genetic network behind NFPA tumorigenesis is not only essential to attain further knowledge of tumor biology, but also plays a fundamental role in the development of efficacious treatment strategies. Differential co-expression network analysis is an outstanding approach for elucidation of groups of genes which show distinct co-expression patterns among phenotypes. In this study, we carried out a differential co-expression network analysis of NFPA-associated transcriptome dataset (n = 40) considering invasive (n = 22) and non-invasive (n = 18) phenotypes. Furthermore, we identified differentially co-expressed and co-regulated mRNA modules, which might be considered as potential systems biomarkers for NFPA prognosis and invasiveness. As a result, we have identified a novel 13-gene module, including CEACAM6, CYP4B1, EIF2S2, HID1, IFFO1, MYO18A, PDCD2, SGIP1, SWSAP1, and four unknown genes (A_24_P127621, A_24_P255786, A_24_P683553, and A_24_P916979), which was able to categorize the patients into two groups as invasive and non-invasive NFPA with distinct prognosis. The prognostic core module genes were associated with progression and prognosis of brain and glandular based cancers as well. Furthermore, these module genes were also expressed in blood, salivary gland, and spinal cord tissues. These results may provide the evidence on featured gene module which might play a prominent role in NFPA prognosis and sub-typing as effective biomarkers and therapeutic targets in the future.

Primary tumors of the posterior pituitary: A systematic review

In 2017, the World Health Organization established that pituicytoma, granular cell tumor (GCT), spindle cell oncocytoma (SCO) and sellar ependymomas (SE) are posterior pituitary tumors (PPT). They probably arise from the pituicytes and may constitute a unique histopathological entity. We carried out a systematic review using PubMed's database. A total of 266 patients with pathological diagnosis of PPT (135 pituicytomas, 69 GCT, 47 SCO, 8 SE and 7 mixed histology tumors) were analyzed. Gender distribution was identical and median age at diagnosis was 48 ± 21.8 years. Main presentation symptoms were visual disorders (n = 142; 58.1%), headache (n = 99; 40.5%), hypopituitarism (n = 84; 34.4%), hypercortisolism (n = 10; 4.1%), polyuriapolydipsia (n = 6; 2.4%) and acromegaly features (n = 5; 2.0%). On MRI, 122 (47.6%) patients showed sellar with suprasellar extension masses, 67 (23.1%) were suprasellar and 63 (24.6%) exclusively sellar. Median tumor size was 22.0 ± 14.2 mm. Two hundred sixty four patients underwent surgery, transphenoidal access was selected in 132 (64.4%) and craniotomy in 58 (28.3%). Complications were hypopituitarism (n = 70; 42.1%), diabetes insipidus (n = 55; 33.1%) and hemorrhage (n = 50; 30.1%). Tumor persisted in 93 patients (45.6%) and recurred in 13 (6.4%). Regarding comparison between main types of PPT, SCO patients were diagnosed later (60.0 vs 47.0 vs 47.0 years, p = 0.023), the tumor was larger 25.0 mm [10.8] vs 20.0 mm [14.2] vs 2.0 mm [15.0] and they were frequently sellar with suprasellar extension tumors (71.7% vs 46.2% vs 32.8%, p = 0.003) compared to pituicytoma and GCT. In conclusion, PPT are rare tumors and have been misdiagnosed mainly as non-functioning pituitary adenomas. Different types of PPT share similar epidemiology, clinical manifestations and surgical outcomes. Surgery is the only curative option but complications and subtotal resection are common.

New and Emerging Biomarkers in Endocrine Pathology

Significant advances in genomics and molecular genetics in recent years have reshaped the practice of endocrine pathology. Pan-genomic studies, including the pioneering ones on papillary thyroid carcinoma, phaeochromocytoma/paraganglioma, and adrenal cortical carcinoma from the Cancer Genome Atlas (TCGA) project, provided a comprehensive integrated genomic analysis of endocrine tumors into distinct molecularly defined subtypes. Better understanding of the molecular landscape and more accurate definition of biological behavior has been accordingly achieved. Nevertheless, how any of these advances are translated into routine practice still remains a challenge in the era of precision medicine. The challenge for modern pathology is to keep up the pace with scientific discoveries by integrating novel concepts in tumor classification, molecular genetics, prognostication, and theranostics. As an example, pathology plays a role in the identification of hereditary disease, while it offers the tools for complementing molecular genetics, for example, validation of variants of unknown significance deriving from targeted sequencing or whole exome/genome sequencing approach. Immunohistochemistry has arisen as a cost-effective strategy in the evaluation either of somatic mutations in tumors and/or germline mutations in patients with familial cancer syndromes. Herein, a comprehensive review focusing on novel and emerging biomarkers is presented in order pathologists and other endocrine-related specialists to remain updated and become aware of potential pitfalls and limitations in the field of endocrine pathology.

Peptide receptor radionuclide therapy for aggressive pituitary tumors: a monocentric experience

In aggressive pituitary tumors (PT) showing local invasion or growth/recurrence despite multimodal conventional treatment, temozolomide (TMZ) is considered a further therapeutic option, while little data are available on peptide receptor radionuclide therapy (PRRT). We analyzed PRRT effectiveness, safety and long-term outcome in three patients with aggressive PT, also reviewing the current literature. Patient #1 (F, giant prolactinoma) received five cycles (total dose 37 GBq) of 111In-DTPA-octreotide over 23 months, after unsuccessful surgery and long-term dopamine-agonist treatment. Patient #2 (M, giant prolactinoma) underwent two cycles (12.6 GBq) of 177Lu-DOTATOC after multiple surgeries, radiosurgery and TMZ. In patient #3 (F, non-functioning PT), five cycles (29.8 GBq) of 177Lu-DOTATOC followed five surgeries, radiotherapy and TMZ. Eleven more cases of PRRT-treated aggressive PT emerged from literature. Patient #1 showed tumor shrinkage and visual/neurological amelioration over 8-year follow-up, while the other PTs continued to grow causing blindness and neuro-cognitive disorders (patient #2) or monolateral amaurosis (patient #3). No adverse effects were reported. Including the patients from literature, 4/13 presented tumor shrinkage and clinical/biochemical improvement after PRRT. Response did not correlate with patients' gender or age, neither with used radionuclide/peptide, but PRRT failure was significantly associated with previous TMZ treatment. Overall, adverse effects occurred only in two patients. PRRT was successful in 1/3 of patients with aggressive PT, and in 4/5 of those not previously treated with TMZ, representing a safe option after unsuccessful multimodal treatment. However, at present, considering the few data, PRRT should be considered only in an experimental setting.

Effect of Hormone Levels and Aging on Cognitive Function of Patients with Pituitary Adenomas Prior to Medical Treatment

BACKGROUND

Cognitive impairments have been reported in patients with pituitary adenomas (PAs). The aim of this research was to demonstrate the effects of hormones and age on cognitive decline in patients with PAs.

METHODS

A total of 64 patients with PA and 69 healthy control subjects (HCs) were recruited for this study. Both PAs and HCs were divided into a younger group (<50 years of age) and an older group (≥50 years of age). Neurocognitive domains were assessed using the Wechsler Adult Intelligence Scale-Chinese Revision (WAIS-RC) and Wechsler Memory Scale-Chinese Revision (WMS-RC) tests. Furthermore, we also investigated the relationship between cognitive domains and tumor volume, and the hormone levels and age of patients with PA.

RESULTS

Several of the cognitive impairments found on the WAIS-RC and WMS-RC tests were more frequently observed in untreated patients with PA. Importantly, no significant correlations were found between cognitive domains and tumor volume after controlling age, sex, and educational levels. Furthermore, several significant correlations were found between cognitive domains and hormone levels, such as free thyroxine and adrenocorticotropic hormone, after controlling age, sex, and educational levels. Finally, the age of the patients was found to correlate with a decrease in memory after controlling sex and educational levels.

CONCLUSIONS

Our findings demonstrate a significant decline in the cognitive performance of patients with PA prior to medical treatment, especially in older patients, which suggests that hormones and age have the ability to interact and aggravate cognitive decline in patients with PA.

Applications of molecular neuro-oncology - a review of diffuse glioma integrated diagnosis and emerging molecular entities

Insights into the molecular underpinnings of primary central nervous system tumors have radically changed the approach to tumor diagnosis and classification. Diagnostic emphasis has shifted from the morphology of a tumor under the microscope to an integrated approach based on morphologic and molecular features, including gene mutations, chromosomal copy number alterations, and gene rearrangements. In 2016, the World Health Organization provided guidelines for making an integrated diagnosis that incorporates both morphologic and molecular features in a subset of brain tumors. The integrated diagnosis now applies to infiltrating gliomas, a category that includes diffusely infiltrating astrocytoma grades II, III, and IV, and oligodendroglioma, grades II and III, thereby encompassing the most common primary intra-axial central nervous system tumors. Other neoplasms such as medulloblastoma, embryonal tumor with multilayered rosettes, certain supratentorial ependymomas, and atypical teratoid/rhabdoid tumor are also eligible for integrated diagnosis, which can sometimes be aided by characteristic immunohistochemical markers. Since 2016, advances in molecular neuro-oncology have resulted in periodic updates and clarifications to the integrated diagnostic approach. These advances reflect expanding knowledge on the molecular pathology of brain tumors, but raise a challenge in rapidly incorporating new molecular findings into diagnostic practice. This review provides a background on the molecular characteristics of primary brain tumors, emphasizing the molecular basis for classification of infiltrating gliomas, the most common entities that are eligible for an integrated diagnosis. We then discuss entities within the diffuse gliomas that do not receive an integrated diagnosis by WHO 2016 criteria, but have distinctive molecular features that are important to recognize because their clinical behavior can influence clinical management and prognosis. Particular attention is given to the histone H3 G34R/G34V mutant astrocytomas, an entity to consider when faced with an infiltrating glioma in the cerebral hemisphere of children and young adults, and to the group of histologically lower grade diffuse astrocytic gliomas with molecular features of glioblastoma, an important category of tumors to recognize due to their aggressive clinical behavior.

The risk/benefit ratio of radiotherapy in pituitary tumors

Radiation therapy (RT) is an effective treatment for patients with either nonfunctioning or secreting pituitary adenomas unsuccessfully treated by surgery and/or medical therapy, resulting in local control of 90-95% at 5-10 years and variable normalization of hormonal hypersecretion for patients with GH-, ACTH-, and prolactin-secreting adenomas in the range of 40-80% at 5 years; however, its use has been limited because of concerns regarding potential late toxicity of radiation and delayed efficacy in normalization of hormone hypersecretion. In the last decades, there have been advances in all aspects of radiation treatment, including more accurate immobilization, imaging, treatment planning and dose delivery. RT has evolved with the development of highly conformal stereotactic techniques and new planning and dose delivery techniques, including intensity-modulated radiotherapy (IMRT) and volumetric modulated arc therapy (VMAT). All these new techniques allow precise and sharply focused radiation delivery reducing the dose to surrounding critical neurovascular and brain structures, and potentially limiting the long-term consequences of radiation treatments. In this review, we present a critical analysis of the more recent available literature on the use of RT in patients with both nonfunctioning and secreting pituitary adenomas, focussing particularly on the risk/benefit ratio of modern radiation techniques.

Increased expression of NAF1 contributes to malignant phenotypes of glioma cells through promoting protein synthesis and associates with poor patient survival

The H/ACA ribonucleoprotein (RNP) complex noncore subunit NAF1 is an indispensable factor during H/ACA RNP maturation, and one of the widely known functions of H/ACA RNP is modulating ribosome biosynthesis. However, the specific biological role and exact mechanism of NAF1 in human cancers including glioma remain largely unclear. In this study, we found that NAF1 was highly expressed in gliomas relative to normal brain tissues, and demonstrated that increased expression of NAF1 was strongly correlated with poor patient survival. Further studies revealed that NAF1 was transcriptionally regulated by c-Myc, NRF2, and telomerase reverse transcriptase (TERT), which are the key molecules associated with malignant progression of gliomas. Moreover, we demonstrated that NAF1 was a functional oncogene in glioma cells through promoting cell growth in vitro and in vivo, survival, migration, and invasion. Mechanistically, NAF1 acted as a rate-limiting controller of cell growth and invasiveness through enhancing 40S subunit assembly and protein synthesis including c-Myc, NRF2, TERT, POLR1A, and POLR2A. These molecules in turn enhanced the transcription and translation of NAF1, thereby forming positive feedback loops between them to promote malignant phenotypes of glioma cells. In addition, our data also showed that NAF1 depletion could trigger ribosome stress, not only impairing ribosomal biosynthesis but also reactivating p53 signaling via blocking MDM2. Taken together, we demonstrated that NAF1 promotes the tumorigenesis and progression of glioma through modulating ribosome assembly and protein synthesis, and predicted that NAF1 may be a potential therapeutic target and valuable prognostic biomarker in gliomas.

Plurihormonal Pit-1 lineage adenoma presenting as meningitis with recurrence after somatostatin analogue

A 21 year-old woman was found to have a pituitary macroadenoma following an episode of haemophilus meningitis. Biochemical TSH and GH excess was noted, although with no clear clinical correlates. She was treated with a somatostatin analogue (SSA), which restored the euthyroid state and controlled GH hypersecretion, but she re-presented with a further episode of cerebrospinal fluid (CSF) leak and recurrent meningitis. Histology following transsphenoidal adenomectomy revealed a Pit-1 lineage plurihormonal adenoma expressing GH, TSH and PRL. Such plurihormonal pituitary tumours are uncommon and even more unusual to present with spontaneous bacterial meningitis. The second episode of CSF leak and meningitis appears to have been due to SSA therapy-induced tumour shrinkage, which is not a well-described phenomenon in the literature for this type of tumour. Learning points: Pit-1 lineage GH/TSH/PRL-expressing plurihormonal pituitary adenomas are uncommon. Moreover, this case is unique as the patient first presented with bacterial meningitis. Inmunohistochemical plurihormonality of pituitary adenomas does not necessarily correlate with biochemical and clinical features of hormonal hypersecretion. Given that plurihormonal Pit-1 lineage adenomas may behave more aggressively than classical pituitary adenomas, accurate pathological characterization of these tumours has an increasing prognostic relevance. Although unusual, a CSF leak and meningitis may be precipitated by SSA therapy of a pituitary macroadenoma via tumour shrinkage.

Pituitary carcinomas: review of the current literature and report of atypical case

Introduction: Pituitary carcinomas are poorly understood, rare entities. They are distinguished from adenomas not by histopathological features but rather by the presence of metastases.Objective: We discuss the diagnosis, mechanism of dissemination and pathogenesis based on a review of the literature and illustrated by a singular case.Case Report: A 59-year-old male presented with a dural-based posterior fossa lesion. He had been diagnosed with a pituitary chromophobe adenoma 43 years earlier that was treated at the time with surgery and radiation therapy. A presumptive diagnosis of a radiation-induced meningioma was made and surgery was recommended. At surgery the tumour resembled a pituitary adenoma. Histopathology, laboratory findings, and the patient's medical history confirmed the final diagnosis of a prolactin-secreting pituitary carcinoma. To our knowledge, this is the longest reported interval between the pituitary adenoma and metastatic lesion diagnosis (43 years).Conclusion: Management should be tailored to individual patient and may include a combination of treatments (surgery, radiation therapy, chemotherapy, and hormone-targeted therapy). Functionally active tumours may be monitored with hormone levels as tumour markers.

Advances and controversies in the classification and grading of pituitary tumors

BACKGROUND

Pituitary tumors are common lesions, and they represent the second most frequent primary brain tumor. Their classification has undergone several changes over time. The World Health Organization conducts periodic expert review/consensus meetings and publishes the results as recommendations for changes in classification, based on advances in molecular and genetic advances. This paper summarizes the results of the 2017 WHO Classification, which recommends several important changes.

PURPOSE

This paper provides a review of the major changes and issues leading to an understanding of the basis for a new pituitary tumor classification. They include the rejection and modification of prior conceptual and pathological characteristics of these neoplasms. There is also considerable concern related to invasive and recurrent pituitary tumors which follow a less benign course than the typical pituitary adenoma.

METHODS

A review of the outcome data for the previously designated "atypical" pituitary tumor category revealed that the former criteria were not adequate to support their ability to predict with accuracy the clinical course of a given tumor. A similar review was accomplished regarding the role of the p53 tumor suppressor mutation. Again, there was no reliable contribution of p53 status to tumor aggressiveness. Other changes have occurred regarding the cytogenetic lineage of the various subtypes of pituitary adenoma. The transcription factors Pit-1, SF-1, and TPit play a major role in determining tumor subtypes and have become part of the classification criteria.

RESULTS

These advances now help provide the background for more reliable and consistent classification of pituitary adenomas. Further definition of aggressive characteristics such as cavernous sinus and dural invasion remain to be considered in the quest to make more accurate prognostic projections based on histopathological analysis.

CONCLUSIONS

The 2017 WHO Classification of Pituitary Tumors provides a more solid basis for accurate and reliable prognostic assessment of these lesions. Further progress undoubtedly will be made as the recommendations of this update are incorporated in to routine use.

The Apoptosis Regulator 14-3-3η and Its Potential as a Therapeutic Target in Pituitary Oncocytoma

The 14-3-3 protein family has attracted much attention in research into the pathogenesis of human tumors because of its involvement in tumorigenesis. In previous studies, we found that 14-3-3η was highly expressed in pituitary oncocytoma. However, the mechanism by which 14-3-3η regulates tumorigenesis in pituitary oncocytoma is unclear. 14-3-3η-binding proteins were investigated in pituitary oncocytoma by immunoprecipitation and proteomic analysis. A total of 443 proteins were identified as 14-3-3η binding proteins. The interactions of 14-3-3η and its binding partners were identified by a network analysis using the STRING database. The network included 433 nodes and 564 edges. PRAS40 (AKT1S1) was a binding protein of 14-3-3η and showed experimental interactions with 14-3-3η in the STRING database. The combined score was 0.407, which suggested a functional link. The 443 binding proteins of 14-3-3η showed enriched molecular signatures in GSEA and GO analysis. PRAS40 (AKT1S1) was enriched in the mTOR signaling pathway. Western blot analysis showed that the relative expression of p-PRAS40 (T246)/PRAS40 was significantly higher in pituitary oncocytoma than in normal pituitary tissues (p < 0.05). R18, a 14-3-3 protein inhibitor, inhibited MMQ cell proliferation after treatment with 8 μM R18 for 48 h compared to the control group (p < 0.01). These results suggest that 14-3-3η may be involved in promoting tumorigenesis in pituitary oncocytoma by interacting with PRAS40 (T246) via the mTOR signaling pathway.

Molecular Network Basis of Invasive Pituitary Adenoma: A Review

Cases with pituitary adenoma comprise 10-25% of intracranial neoplasm, being the third most common intracranial tumor, most of the adenomas are considered to be benign. About 35% of pituitary adenomas are invasive. This review summarized the known molecular basis of the invasiveness of pituitary adenomas. The study pointed out that hypoxia-inducible factor-1α, pituitary tumor transforming gene, vascular endothelial growth factor, fibroblast growth factor-2, and matrix metalloproteinases (MMPs, mainly MMP-2, and MMP-9) are core molecules responsible for the invasiveness of pituitary adenomas. The reason is that these molecules have the ability to directly or indirectly induce cell proliferation, epithelial-to-mesenchymal transition, angiogenesis, degradation, and remodeling of extracellular matrix. HIF-1α induced by hypoxia or apoplexy inside the adenoma might be the initiating factor of invasive transformation, followed with angiogenesis for overexpressed VEGF, EMT for overexpressed PTTG, degradation of ECM for overexpressed MMPs, creating a suitable microenvironment within the tumor. Together, they form a complex interactive network. More investigations are required to further elucidate the mechanisms underlying the invasiveness of pituitary adenomas.

Immunohistochemical Study of NR2C2, BTG2, TBX19, and CDK2 Expression in 31 Paired Primary/Recurrent Nonfunctioning Pituitary Adenomas

This study investigated potential markers for predicting nonfunctioning pituitary adenoma (NFPA) invasion and recurrence by high-throughput tissue microarray analyses. We retrospectively studied two groups of patients: 60 nonrecurrent NFPA cases that included noninvasion and invasion subtypes and 43 recurrent cases that included primary NFPA. A total of 31 paired patient samples were evaluated (12 patients with one surgery and 31 who had undergone two operations, with both tumors analyzed). Expressions of nuclear receptor subfamily 2 group C member 2 (NR2C2), B cell translocation gene 2, T-box-19 (TBX19), and cyclin-dependent kinase 2 (CDK2) in surgically resected specimens were assessed by immunohistochemistry. The relationships between marker expression and clinical characteristics including age, sex, tumor volume, and follow-up time were analyzed. Tumor volume and invasion as well as follow-up time were significantly associated with invasion and recurrence (P < 0.01). Of the 60 nonrecurrent samples, 15/41 and 13/19 showed high NR2C2 expression in the noninvasion and invasion groups, respectively (χ ² =5.287, P = 0.021). NR2C2 was also overexpressed in 43 primary recurrent cases (χ ² =5.433, P = 0.02), whereas CDK2 (χ ² = 11.242, P = 0.001) and TBX19 (χ ² = 4.875, P = 0.027) were downregulated. In the 31 paired samples, NR2C2 was more highly expressed in the recurrent as compared to the primary tumor. High NR2C2 expression was associated with NFPA invasion, recurrence, and progression, while TBX19 and CDK2 were associated with NFPA recurrence.

[Morphofunctional features of non-functioning pituitary adenomas]

Non-functioning pituitary adenomas (NFPAs) account for about 30% of all pituitary tumors. NFPAs are characterized by the lack of secretory potential or its weak expression insufficient for determination of the blood level of adenohypophyseal tropic hormones and for development of a specific clinical picture. Morphologically, NFPAs are a heterogeneous group of tumors, the classification of which was previously based only on immunoreactivity for pituitary tropic hormones. The WHO revised its Classification of Tumors of Endocrine Organs (4th edition) in 2017. The main changes relate to adenohypophysial-cell lineage for the designation of adenomas into subtypes. The introduction of transcription factor antibodies has become a fundamentally new approach to the classification of NFPAs, which is necessary to recognize less differentiated tumor types. This paper provides information on the new histopathological classification of pituitary adenomas, on the theories of silent adenomas, and on the proliferative and prognostic markers of NFPAs.

Posterior pituitary tumours: the spectrum of a unique entity. A clinical and histological study of a large case series

PURPOSE

In 2017, the WHO established that pituicytoma, granular cell tumour (GCT) and spindle cell oncocytoma (SCO) are posterior pituitary tumours (PPT). Recent data suggests that these tumours probably arise from the pituicytes and may constitute a spectrum of a unique histopathological entity. Our aim is to report the clinical findings and surgical outcomes of 16 patients with PPT. We also evaluated the tissue specimens available in light of current knowledge.

METHOD

Cross-sectional study with retrospective data.

RESULTS

PPT were 7 pituicytomas, 3 GCT and 6 SCO. Patients mean age was 55 years old and 75% were female. Basal hormonal study showed hyperprolactinemia (43.7%) and hypopituitarism (37.5%). There was no case of diabetes insipidus (DI). MRI showed sellar/suprasellar masses with mean size of 19.7mm. PPT was not suspected in any patient. Fifteen patients underwent surgery and complications were common: 20% had perioperative bleeding (one patient died because of a massive haemorrhage), 57.1% hypopituitarism, 35.7% permanent DI and 21.4% underwent a second surgery. Pathological findings shown positivity for thyroid transcription factor 1, vimentin and negativity for cytokeratin and chromogranin A in all specimens evaluated. S100 protein was positive in 88.8% of tumours. Ki67 was ≥ 3% in 66.6% and ranged from 4-7% in SCO.

CONCLUSION

PPT have similar histology, clinical features and are frequently misdiagnosed as nonfunctioning pituitary tumours. However, post-surgical complications including haemorrhage are common. A high clinical suspicion is needed to presume the diagnosis prior surgery and diminish the high morbidity of these tumours.

The Epigenomics of Pituitary Adenoma

Background: The vast majority of pituitary tumors are benign and behave accordingly; however, a fraction are invasive and are more aggressive, with a very small fraction being frankly malignant. The cellular pathways that drive transformation in pituitary neoplasms are poorly characterized, and current classification methods are not reliable correlates of clinical behavior. Novel techniques in epigenetics, the study of alterations in gene expression without changes to the genetic code, provide a new dimension to characterize tumors, and may hold implications for prognostication and management. Methods: We conducted a review of primary epigenetic studies of pituitary tumors with a focus on histone modification, DNA methylation, and transcript modification. Results: High levels of methylation have been identified in invasive and large pituitary tumors. DNA methyltransferase overexpression has been detected in pituitary tumors, especially in macroadenomas. Methylation differences at CpG sites in promoter regions may distinguish several types of tumors from normal pituitary tissue. Histone modifications have been linked to increased p53 expression and longer progression-free survival in pituitary tumors; sirtuins are expressed at higher values in GH-expressing compared to nonfunctional adenomas and correlate inversely with size in somatotrophs. Upregulation in citrullinating enzymes may be an early pathogenic marker of prolactinomas. Numerous genes involved with cell growth and signaling show altered methylation status for pituitary tumors, including cell cycle regulators, components of signal transduction pathways, apoptotic regulators, and pituitary developmental signals. Conclusions: The limited clinical predictive capacity of the current pituitary tumor classification system suggests that tumor subclasses likely remain to be discovered. Ongoing epigenetic studies could provide a basis for adding methylation and/or acetylation screening to standard pituitary tumor workups. Identifying robust correlations between tumor epigenetics and corresponding histological, radiographic, and clinical course information could ultimately inform clinical decision-making.

Non-secreting pituitary tumours characterised by enhanced expression of YAP/TAZ

Tumours of the anterior pituitary can manifest from all endocrine cell types but the mechanisms for determining their specification are not known. The Hippo kinase cascade is a crucial signalling pathway regulating growth and cell fate in numerous organs. There is mounting evidence implicating this in tumour formation, where it is emerging as an anti-cancer target. We previously demonstrated activity of the Hippo kinase cascade in the mouse pituitary and nuclear association of its effectors YAP/TAZ with SOX2-expressing pituitary stem cells. Here, we sought to investigate whether these components are expressed in the human pituitary and if they are deregulated in human pituitary tumours. Analysis of pathway components by immunofluorescence reveals pathway activity during normal human pituitary development and in the adult gland. Poorly differentiated pituitary tumours (null-cell adenomas, adamantinomatous craniopharyngiomas (ACPs) and papillary craniopharyngiomas (PCPs)), displayed enhanced expression of pathway effectors YAP/TAZ. In contrast, differentiated adenomas displayed lower or absent levels. Knockdown of the kinase-encoding Lats1 in GH3 rat mammosomatotropinoma cells suppressed Prl and Gh promoter activity following an increase in YAP/TAZ levels. In conclusion, we have demonstrated activity of the Hippo kinase cascade in the human pituitary and association of high YAP/TAZ with repression of the differentiated state both in vitro and in vivo. Characterisation of this pathway in pituitary tumours is of potential prognostic value, opening up putative avenues for treatments.

Hypopituitarism after Gamma Knife radiosurgery for pituitary adenomas: a multicenter, international study

OBJECTIVE

Recurrent or residual adenomas are frequently treated with Gamma Knife radiosurgery (GKRS). The most common complication after GKRS for pituitary adenomas is hypopituitarism. In the current study, the authors detail the timing and types of hypopituitarism in a multicenter, international cohort of pituitary adenoma patients treated with GKRS.

METHODS

Seventeen institutions pooled clinical data obtained from pituitary adenoma patients who were treated with GKRS from 1988 to 2016. Patients who had undergone prior radiotherapy were excluded. A total of 1023 patients met the study inclusion criteria. The treated lesions included 410 nonfunctioning pituitary adenomas (NFPAs), 262 cases of Cushing's disease (CD), and 251 cases of acromegaly. The median follow-up was 51 months (range 6-246 months). Statistical analysis was performed using a Cox proportional hazards model to evaluate factors associated with the development of new-onset hypopituitarism.

RESULTS

At last follow-up, 248 patients had developed new pituitary hormone deficiency (86 with NFPA, 66 with CD, and 96 with acromegaly). Among these patients, 150 (60.5%) had single and 98 (39.5%) had multiple hormone deficiencies. New hormonal changes included 82 cortisol (21.6%), 135 thyrotropin (35.6%), 92 gonadotropin (24.3%), 59 growth hormone (15.6%), and 11 vasopressin (2.9%) deficiencies. The actuarial 1-year, 3-year, 5-year, 7-year, and 10-year rates of hypopituitarism were 7.8%, 16.2%, 22.4%, 27.5%, and 31.3%, respectively. The median time to hypopituitarism onset was 39 months.In univariate analyses, an increased rate of new-onset hypopituitarism was significantly associated with a lower isodose line (p = 0.006, HR = 8.695), whole sellar targeting (p = 0.033, HR = 1.452), and treatment of a functional pituitary adenoma as compared with an NFPA (p = 0.008, HR = 1.510). In multivariate analyses, only a lower isodose line was found to be an independent predictor of new-onset hypopituitarism (p = 0.001, HR = 1.38).

CONCLUSIONS

Hypopituitarism remains the most common unintended effect of GKRS for a pituitary adenoma. Treating the target volume at an isodose line of 50% or greater and avoiding whole-sellar radiosurgery, unless necessary, will likely mitigate the risk of post-GKRS hypopituitarism. Follow-up of these patients is required to detect and treat latent endocrinopathies.

Aggressive and malignant pituitary tumours: state-of-the-art

Pituitary adenomas are unique in multiple ways. They are rarely malignant in terms of metastases; yet, they may be aggressive. Their cancerous potential is defined in a classic oncological way by the ability to metastasise, and therefore, it has been crucial to differentiate this process from aggressive behaviour, characterised as a particularly invasive and/or recurrent behaviour and resistance to common modalities of therapy. Recently, however, important changes have been introduced to the diagnosis and management of aggressive and malignant pituitary tumours including the 4th edition of the World Health Organization (WHO) classification for endocrine tumours (2017) as well as ESE Clinical Guidelines (2018), although an attempt to establish predictive and/or prognostic markers of clinical aggressiveness remains difficult. In this review, we focus on a group of pituitary tumours causing significant problems in clinical practice and requiring multidisciplinary input. We summarise updates in definitions of tumour invasiveness, aggressiveness and malignant transformation, as well as histological classification, and emphasise the new considerations regarding aggressive and malignant potential and its relationship to therapeutic strategies.