Pathology and molecular genetics of meningioma: recent advances

Diarylpentanoid, a curcumin analog, inhibits malignant meningioma growth in both in vitro and in vivo models

BACKGROUND

Malignant meningioma metastasizes systemically, primarily due to its role in epithelial-mesenchymal transition. Although the prognosis is extremely poor, drug development efforts have been limited, because this tumor is categorized as a rare form.

AIM

To examine growth suppressive effect of GO-Y030, a diarylpentanoid curcumin analog, (1E,4E)-1,5-bis [3,5-bis (methoxymethoxy) phenyl] penta-1,4-dien-3-one against the malignant meningioma.

METHODS

The growth suppression of malignant meningioma cells by GO-Y022 and GO-Y030 were examined, using IOMM-Lee and HKBMM cell lines. Male nude mice aged eight weeks, specifically BALB/cSlc-nu/nu mice received a subcutaneous inoculation of IOMM-Lee (10⁷ cells/site) on their back and 30 μg/kg of recombinant hepatocellular growth factor (HGF) was injected into the tumor every three days. After confirmed the growth tumor mass, 500 μL of GO-Y030 diluted with PBS were administrated intraperitoneally daily at doses of 1 mg/kg and 2 mg/kg, respectively.

RESULTS

GO-Y030 exhibits a growth inhibitory effect on malignant meningioma cell lines, IOMM-Lee and HKBMM ranging from 0.8-2.0 μM in vitro. Notably, GO-Y030’s inhibitory effect is about 10 to 16^th times more potent than that of curcumin, which has previously demonstrated potential in combating malignant meningioma. In mouse models, the intraperitoneal administration of GO-Y030 effectively suppresses the growth of malignant meningioma tumors that have been inoculated in the back (P = 0.002). High-performance liquid chromatography analysis has confirmed the distribution of GO-Y030 in the bloodstream and brain tissue. Moreover, GO-Y030 demonstrates the ability to significantly suppress HGF (P < 0.01), nuclear factor kappa B (P < 0.001), and N-cadherin (P < 0.001), all of which contribute to the epithelial-mesenchymal transition.

CONCLUSION

GO-Y030 holds promise as a potent compound for the systemic inhibition of malignant meningioma. GO-Y030 has higher tumor growth inhibitory effect against meningiomas than curcumin, which is known to have antitumor activity through multi-molecular target control resulting in apoptosis induction. GO-Y030 controls at least three molecules of HGF, nuclear factor kappa B, and N-cadherin.

Prevalence and symptoms of incidental meningiomas: a population-based study

BACKGROUND

Meningioma is the most common intracranial primary neoplasm and is often discovered accidentally. Common and non-specific symptoms such as headache and dizziness may be wrongfully attributed to meningiomas, which can lead to unnecessary surgery and anxiety for the patient. Understanding the prevalence of meningioma is therefore pivotal to assess the burden of this disease and determine indications for surgery.

METHOD

Participants in this study were recruited through "The Gothenburg H70 Birth cohort study" wherein the health of 70-year-olds is examined. Clinical characteristics and symptoms such as sex, body mass index, history of smoking, previous head trauma, previous seizure, headache, dizziness, dementia, and life quality were evaluated. The associations between these variables and the presence of meningioma on MRI were determined.

RESULTS

MRI examinations were collected from 792 participants (415 [52.4%] women) in "The Gothenburg H70 Birth cohort study". The prevalence of meningioma was 1.8% (n = 14). Meningiomas were more common in women (n = 12) than men, but no other significant differences were observed between participants with and without meningiomas.

CONCLUSIONS

Meningiomas are common among older women, yet often asymptomatic. Caution should be exercised when attributing symptoms to incidentally discovered small meningiomas, and a conservative approach to treatment may be warranted in these cases.

Deciphering extracranial metastasis in high-grade meningiomas: insights from a case study and literature review

Introduction and importance

These high-grade meningiomas have higher recurrence rates and poorer survival outcomes compared to benign variants. This study presents a case of metastasis in a high-grade meningioma and a comprehensive analysis of the literature published between 2000 and 2023, including only original studies focused on extracranial metastasis.

Case presentation

We report the case of a 45-year-old female who presented with progressive left-sided weakness and partial seizures. Imaging revealed a large, lobulated extra-axial mass in the right parietal parasagittal region, which was surgically resected and diagnosed as an anaplastic meningioma (WHO grade III). Despite an initial recovery, the patient experienced tumor recurrence with local invasion, multiple metastases to the contralateral brain, liver, lung, spine, and long bone. Various treatments, including radiotherapy, chemotherapy, and surgery, were employed, but the disease progressed, leaving the patient bed-bound at 8 years follow up.

Clinical discussion

In our literature review, encompassing 247 patients with extracranial metastasis of meningiomas from seven studies, the lungs and bones were the most common metastatic sites. Patients with grade III meningiomas had poorer survival outcomes than those with grade II. Gross total resection (GTR) was associated with improved progression-free survival, while recurrence markedly reduced overall survival, underscoring the aggressive nature of metastatic meningiomas and the importance of early, comprehensive treatment strategies.

Conclusion

Extracranial metastasis in high-grade meningiomas poses significant diagnostic and therapeutic challenges. Our analysis underscores the complexity of managing these cases and highlights the critical need for early identification of high-risk patients and tailored treatment protocols to improve long-term outcomes.

Intracranial meningioma: A review of recent and emerging data on the utility of preoperative imaging for management

Meningiomas are the most common neoplasms of the central nervous system, accounting for approximately 40% of all brain tumors. Surgical resection represents the mainstay of management for symptomatic lesions. Preoperative planning is largely informed by neuroimaging, which allows for evaluation of anatomy, degree of parenchymal invasion, and extent of peritumoral edema. Recent advances in imaging technology have expanded the purview of neuroradiologists, who play an increasingly important role in meningioma diagnosis and management. Tumor vascularity can now be determined using arterial spin labeling and dynamic susceptibility contrast-enhanced sequences, allowing the neurosurgeon or neurointerventionalist to assess patient candidacy for preoperative embolization. Meningioma consistency can be inferred based on signal intensity; emerging machine learning technologies may soon allow radiologists to predict consistency long before the patient enters the operating room. Perfusion imaging coupled with magnetic resonance spectroscopy can be used to distinguish meningiomas from malignant meningioma mimics. In this comprehensive review, we describe key features of meningiomas that can be established through neuroimaging, including size, location, vascularity, consistency, and, in some cases, histologic grade. We also summarize the role of advanced imaging techniques, including magnetic resonance perfusion and spectroscopy, for the preoperative evaluation of meningiomas. In addition, we describe the potential impact of emerging technologies, such as artificial intelligence and machine learning, on meningioma diagnosis and management. A strong foundation of knowledge in the latest meningioma imaging techniques will allow the neuroradiologist to help optimize preoperative planning and improve patient outcomes.

The Impact of Molecular and Genetic Analysis on the Treatment of Patients with Atypical Meningiomas

Meningiomas represent approximately 40% of all primary tumors of the central nervous system (CNS) and, based on the latest World Health Organization (WHO) guidelines, are classified into three grades and fifteen subtypes. The optimal treatment comprises gross total tumor resection. The WHO grade and the extent of tumor resection assessed by the Simpson grading system are the most important predictors of recurrence. Atypical meningiomas, a grade 2 meningioma, which represent almost a fifth of all meningiomas, have a recurrence rate of around 50%. Currently, different histopathologic, cytogenetic, and molecular genetic alterations have been associated with different meningioma phenotypes; however, the data are insufficient to enable the development of specific treatment plans. The optimal treatment, in terms of adjuvant radiotherapy and postoperative systemic therapy in atypical meningiomas, remains controversial, with inconclusive evidence in the literature and existing studies. We review the recent literature to identify studies investigating relevant atypical meningioma biomarkers and their clinical application and effects on treatment options.

Intracranial meningiomas at a tertiary hospital: Spectrum of MRI findings with histopathologic correlation

Background

Intracranial meningiomas consist of a heterogenous group of histological subtypes, some of which are rare. Data that may play an important role in neurosurgical decision-making regarding the incidence and MRI features of these histological subtypes in the South African population groups, are lacking.

Objectives

This study aimed to assess the spectrum of MRI findings and histological subtypes of meningiomas in the South African context, with the goal of improving the paucity of literature on the topic.

Method

A retrospective review of the MRI features of 41 cases of histologically confirmed intracranial meningiomas was performed at a tertiary hospital level. Imaging features were audited and correlated with histological subtypes during statistical analysis.

Results

Eleven different histological subtypes of meningioma were encountered. World Health Organization (WHO) Grade I meningothelial meningiomas were the most common histological subgroup. Overall, meningiomas were found to be predominantly isointense to grey matter on T1-weighted imaging, irrespective of the histological subtype, with greater signal variability on T2-weighted imaging. Morphologies of specific subtypes are in keeping with the literature.

Conclusion

Analysis of this series of intracranial meningiomas did not demonstrate statistically significant differences in MRI features between histological subtypes to allow for accurate preoperative prediction of meningioma subtype or WHO grade. This highlights the importance of definitive histopathological diagnosis rather than over-reliance on presumed benign imaging features.

Contribution

This original research article discusses the impact of histological subtype on the MRI appearance of intracranial meningiomas, with the aim to improve the paucity of literature on the subject in the context of the South African population.

Noncoding RNA landscape and their emerging roles as biomarkers and therapeutic targets in meningioma

Meningiomas are among the most prevalent primary CNS tumors in adults, accounting for nearly 38% of all brain neoplasms. The World Health Organization (WHO) grade assigned to meningiomas guides medical care in patients and is primarily based on tumor histology and malignancy potential. Although often considered benign, meningiomas with complicated histology, limited accessibility for surgical resection, and/or higher malignancy potential (WHO grade 2 and WHO grade 3) are harder to combat, resulting in significant morbidity. With limited treatment options and no systemic therapies, it is imperative to understand meningioma tumorigenesis at the molecular level and identify novel therapeutic targets. The last decade witnessed considerable progress in understanding the noncoding RNA landscape of meningioma, with microRNAs (miRNAs) and long noncoding RNAs (lncRNAs) emerging as molecular entities of interest. This review aims to highlight the commonly dysregulated miRNAs and lncRNAs in meningioma and their correlation with meningioma progression, malignancy, recurrence, and radioresistance. The role of "key" miRNAs as biomarkers and their therapeutic potential has also been reviewed in detail. Furthermore, current and emerging therapeutic modalities for meningioma have been discussed, with emphasis on the need to identify and subsequently employ clinically relevant miRNAs and lncRNAs as novel therapeutic targets and biomarkers.

Domestic Animal Models of Central Nervous System Tumors: Focus on Meningiomas

Intracranial primary tumors (IPTs) are aggressive forms of malignancies that cause high mortality in both humans and domestic animals. Meningiomas are frequent adult IPTs in humans, dogs, and cats, and both benign and malignant forms cause a decrease in life quality and survival. Surgery is the primary therapeutic approach to treat meningiomas, but, in many cases, it is not resolutive. The chemotherapy and targeted therapy used to treat meningiomas also display low efficacy and many side effects. Therefore, it is essential to find novel pharmacological approaches to increase the spectrum of therapeutic options for meningiomas. This review analyzes the similarities between human and domestic animal (dogs and cats) meningiomas by evaluating the molecular and histological characteristics, diagnosis criteria, and treatment options and highlighting possible research areas to identify novel targets and pharmacological approaches, which are useful for the diagnosis and therapy of this neoplasia to be used in human and veterinary medicine.

Recent advances in the molecular prognostication of meningiomas

Meningiomas are the most common primary intracranial neoplasm. While traditionally viewed as benign, meningiomas are associated with significant patient morbidity, and certain meningioma subgroups display more aggressive and malignant behavior with higher rates of recurrence. Historically, the risk stratification of meningioma recurrence has been primarily associated with the World Health Organization histopathological grade and surgical extent of resection. However, a growing body of literature has highlighted the value of utilizing molecular characteristics to assess meningioma aggressiveness and recurrence risk. In this review, we discuss preclinical and clinical evidence surrounding the use of molecular classification schemes for meningioma prognostication. We also highlight how molecular data may inform meningioma treatment strategies and future directions.

T1 and ADC histogram parameters may be an in vivo biomarker for predicting the grade, subtype, and proliferative activity of meningioma

OBJECTIVE

To investigate the value of histogram analysis of T1 mapping and diffusion-weighted imaging (DWI) in predicting the grade, subtype, and proliferative activity of meningioma.

METHODS

This prospective study comprised 69 meningioma patients who underwent preoperative MRI including T1 mapping and DWI. The histogram metrics, including mean, median, maximum, minimum, 10th percentiles (C10), 90th percentiles (C90), kurtosis, skewness, and variance, of T1 and apparent diffusion coefficient (ADC) values were extracted from the whole tumour and peritumoural oedema using FeAture Explorer. The Mann-Whitney U test was used for comparison between low- and high-grade tumours. Receiver operating characteristic (ROC) curve and logistic regression analyses were performed to identify the differential diagnostic performance. The Kruskal-Wallis test was used to further classify meningioma subtypes. Spearman's rank correlation coefficients were calculated to analyse the correlations between histogram parameters and Ki-67 expression.

RESULTS

High-grade meningiomas showed significantly higher mean, maximum, C90, and variance of T1 (p = 0.001-0.009), lower minimum, and C10 of ADC (p = 0.013-0.028), compared to low-grade meningiomas. For all histogram parameters, the highest individual distinctive power was T1 C90 with an AUC of 0.805. The best diagnostic accuracy was obtained by combining the T1 C90 and ADC C10 with an AUC of 0.864. The histogram parameters differentiated 4/6 pairs of subtype pairs. Significant correlations were identified between Ki-67 and histogram parameters of T1 (C90, mean) and ADC (C10, kurtosis, variance).

CONCLUSION

T1 and ADC histogram parameters may represent an in vivo biomarker for predicting the grade, subtype, and proliferative activity of meningioma.

KEY POINTS

• The histogram parameter based on T1 mapping and DWI is useful to preoperatively evaluate the grade, subtype, and proliferative activity of meningioma. • The combination of T1 C90 and ADC C10 showed the best performance for differentiating low- and high-grade meningiomas.

Correlation between Radiological Images and Histopathological Type of Meningioma: A Cohort Study

Background

Histologically affirmed meningiomas represent 37.6% of all essential central nervous system tumors and half of all types of critical central nervous system tumors. This study compares computed tomography (CT) scans of the head with histological findings to establish the characteristics of different types of meningiomas observed in eastern Indonesia.

Methods

This prospective study evaluated 224 patients by examining the correlation between histological and CT data collected from January to December 2020 at Wahidin Sudirohusodo Hospital, Makassar, Indonesia. We assessed data including the location of pre- and post-contrast CT scans, number of tumors, margin, density, contrast enhancement, bony reaction, calcification, and perifocal edema. Patients underwent biopsies followed by an examination of the anatomical pathology tissue.

Results

The female-to-male ratio of participants was 4.2 to 1, and the highest incidence was observed in participants of both genders aged 40-60 years. The most common meningioma subtype was meningothelial, while the most commonly observed locations involved the convexity and sphenoid regions. Most meningiomas had well-defined margins on CT imaging: 54.5% of patients exhibited isodense lesions on pre-contrast scans, and 64.7% exhibited high-contrast enhancement. Bone destruction developed in 4.1% of patients, while hyperostosis was observed in 17.4%, and calcification was present in 10.3% of the participants. Edema was identified in 65.2% of cases, of which moderate edema was the most common manifestation.

Conclusion

Meningioma should be highly suspected in female patients aged 40-60 with isodense lesions on pre-contrast CT scans and high-contrast enhancement on post-contrast CT scans. Meningiomas were primarily classified as convexity meningiomas with well-defined margins. The presence of hyperostosis, calcification, and brain edema supported the meningioma diagnosis.

Human TERT Promoter Mutations in Atypical and Anaplastic Meningiomas

Background: The role of telomerase reverse transcriptase (TERT) gene promoter mutations (pTERT) in atypical and anaplastic meningiomas remains controversial. This study aimed to evaluate their impact on the histologic diagnosis and prognosis in a retrospective series of 74 patients with atypical and anaplastic meningioma, including disease progression and relapse. A supplementary panel of 21 benign tumours was used as a control cohort. Materials and Methods: The mutation rate of the pTERT gene was assessed by Sanger sequencing. ATRX protein expression was detected by immunohistochemistry. The phenotypic and genotypic intra-tumour heterogeneity was studied in a sub-group of 12 cases using a Molecular Machines & Industries (MMI) CellCut laser microdissection (LMD) system. Results: pTERT mutations were detected in 12/74 (17.6%) malignant meningiomas. The mutation rate was significantly higher in anaplastic meningiomas (7/23, 30.4%) compared to atypical tumours (5/48, 10.4%) (p = 0.0443). In contrast, the mutation rate was < 5% in benign tumours. All pTERT mutant cases retained nuclear ATRX immunoreactivity. pTERT mutations were significantly associated with the histologic grade (p = 0.0443) and were adverse prognostic factors for anaplastic tumours (p = 0.06). Conclusion: We reported on the pTERT mutation spectrum in malignant meningiomas, supporting their use in the prognostic classification.

Ectopic thoracic meningioma: a diagnostically challenging case

Whilst meningiomas are common neoplasms of the central nervous system; ectopic meningiomas are very rare. When they do occur, they are typically in the head and neck. Due to their rarity, they propose a diagnostic challenge with interesting pathological findings. To date, only seven ectopic meningiomas arising in the mediastinum have been reported in the literature. We aim to shift the focus on the diagnostic journey of this rare entity which involved various imaging and histopathological techniques. Our patient was successfully treated with no complications after four years through input from specialists and the multidisciplinary team.

Foramen magnum meningioma with excessive calcification and no dura tail sign: A case report

RATIONALE

Foramen magnum meningiomas are very rare lesions. They frequently originate from the arachnoid cells at the dura matter of the craniocervical junction. Foramen magnum meningiomas are challenging for neurosurgeons because of the complex anatomy of foramen magnum. We present a rare case of FMM with excessive calcification and without the dura tail sign which made the lesion mimic a teratoma.

PATIENTS CONCERNS

A 63 years old woman presented with progressive numbness and hyperesthesia of the shoulders and upper limbs for 2 and half years. She also experienced occasional headaches and dizziness with no nausea, vomiting or fever.

DIAGNOSES

Computed tomography scan, and magnetic resonance imaging revealed a calcified mass at occipital cistern. The lesion did not show the usual "dura tail sign" which made it mimic a teratoma on magnetic resonance imaging. Histopathology established meningioma.

INTERVENTION

The tumor was completely resected via suboccipital approach.

OUTCOMES

Two years follow-up revealed no recurrence of the lesion and no neurological deficits.

LESSONS

We advocate the use of electromyographic and auditory brainstem responses to monitor the inferior cranial nerves because the tumor often adheres to these nerves.

Double Meningioma: A Case of Two Fibrous Meningiomas Coexisting Isolatedly in Meningothelial Meningioma

Meningiomas are the most common intracranial primary neoplasm in adults, and show various histological subtypes, indicating heterogeneous clinical and molecular genetic characteristics. Different subtypes of meningioma coexisting independently within the main tumor of another different subtype is a quite rare clinical situation. A 69-year-old woman presented with a several- year history of dizziness as a non-specific complaint. Magnetic resonance imaging (MRI) revealed an extra-axial mass lesion in the left parieto-occipital region including two well-demarcated, round mass components. Total resection was performed via left parieto-occipital craniotomy. Two white masses were identified within the main tumor, with neither showing dural attachments. Pathological findings showed the main mass represented meningothelial meningioma and the demarcated mass lesions were both fibrous meningiomas. No transitional features existed between these subtypes. No differences in genetic characteristics were evident between subtypes of meningioma. We have described, apparently for the first time, a case of two fibrous meningiomas coexisting in an isolated manner in meningothelial meningioma with the similar molecular genetic profile.

Characterization of Progesterone Receptor Expression in Intracranial Meningiomas of Patients Treated in a High-Complexity Hospital in Bogota, Colombia

Background Meningiomas are the single most common brain tumor. The incidence of these tumors increases with age; different studies have shown that meningiomas usually appear after the age of 50. These tumors are more common in women than in men, and women are twice as likely to suffer from the condition. Surgery is the primary form of treatment, which can be curative with complete resection. If the tumor is unresectable or other treatments such as surgery and radiotherapy have failed, hormonal therapy or chemotherapy may be considered. There is limited information about the clinical, demographic, and histopathological characteristics of these tumors in the population of Bogotá, Colombia. Objective To evaluate the expression of progesterone receptors in patients over 18 years old who have been diagnosed with meningiomas in a high-complexity hospital in Bogota, Colombia, and to describe the demographic and histopathological characteristics of these patients. Methods This is a descriptive and retrospective case series. Patients with meningioma who underwent surgical resection at a high-complexity hospital in Bogota, Colombia, from 2016 to 2019 were retrospectively identified and studied. Demographic variables, such as age and gender, were extracted from the clinical chart. Indirect immunoperoxidase staining was carried out for the progesterone receptor (PR) and Ki67. PR is analyzed as positive and negative, and the Ki67 proliferation index was determined. Results Thirty-two meningiomas from patients who underwent surgery were available for analysis. Twenty-five (78.1%) were positive for PR, 71.8% were females, and 93% were World Health Organization (WHO) grade I. Meningothelial (28%), fibrous (25%), and transitional (25%) meningiomas were the most frequent subtypes, correspondingly. The Ki67 mean value was 1.14 (0.11-10.71). Conclusion Our case series showed a greater frequency of meningiomas in women, with a high PR expression and a low Ki67 proliferation rate. These data correlate with literature worldwide.

WHO classification of meningiomas-A single institutional experience

INTRODUCTION

Meningiomas are among the most common intracranial neoplasms worldwide. The World Health Organization (WHO) has classified the neoplasm into three grades with each grade having several histological variants. Several studies done in blacks have shown differences with Caucasian populations regarding the occurrence of histological variants. Our study sought to examine the histological variants of meningioma seen in a predominantly black population using the WHO grading system.

METHODS

We conducted a retrospective study of all meningiomas seen in our hospital facility for over twenty years. An analysis of data from all the patients diagnosed with meningioma, who also had surgical biopsies taken, was done. The meningiomas were graded using the WHO grading system and also classified into different histological variants within each grade as described by the WHO study group.

RESULTS

The study included a total number of 163 biopsies. There were more females diagnosed with meningiomas with a female to male ratio of 1.4. Most of the tumors were grade one, however, there were more males with malignant meningiomas. Transitional meningiomas were the most commonly seen variants among the grade one tumors while atypical and anaplastic were most common in grades two and three, respectively.

CONCLUSION

A larger population-based study is needed to provide epidemiological data on the occurrence of meningiomas in blacks.

Facial Nerve Meningioma: A Case Mimicking Facial Nerve Schwannoma

Facial nerve meningioma is exceedingly rare and tends to affect the geniculate ganglion. We present a case of facial nerve meningioma located in the internal auditory canal with a "labyrinthine tail," mimicking facial nerve schwannoma. The clinical and radiological features, growth patterns, and surgical management were reviewed. Progressive facial paralysis was the main syndrome, similar to other facial nerve tumors. When facial nerve function is worse than House-Brackmann grade III, surgical resection should be performed with facial nerve reconstruction.

Liver Metastasis from Typical Meningioma

BACKGROUND

Extracranial metastases from atypical meningioma are not usually found; they are sometimes found in lung, bone or scalp, but atypical meningioma in the liver is extremely rare.

CASE DESCRIPTION

We report a case of a 55-year-old patient with atypical meningioma, treated with surgical resection in 2005, who accepted a second surgical resection in 2015 by the same surgeon, caused by a liver metastasis 4 years after the second surgical resection.

CONCLUSIONS

We have analyzed the cytological findings of a metastastic meningioma with particular focus on pathological and immunohistochemical assessment. These results could improve the knowledge of surgeons about meningioma types and guide them to solve clinical incidents.

Identification of a Transcription Factor-microRNA-Gene Coregulation Network in Meningioma through a Bioinformatic Analysis

Background

Meningioma is a prevalent type of brain tumor. However, the initiation and progression mechanisms involved in the meningioma are mostly unknown. This study aimed at exploring the potential transcription factors/micro(mi)RNAs/genes and biological pathways associated with meningioma.

Methods

mRNA expressions from GSE88720, GSE43290, and GSE54934 datasets, containing data from 83 meningioma samples and eight control samples, along with miRNA expression dataset GSE88721, which had 14 meningioma samples and one control sample, were integrated analyzed. The bioinformatics approaches were used for identifying differentially expressed genes and miRNAs, as well as predicting transcription factor targets related to the differentially expressed genes. The approaches were also used for gene ontology term analysis and biological pathway enrichment analysis, construction, and analysis of protein-protein interaction network, and transcription factor-miRNA-gene coregulation network construction.

Results

Fifty-six upregulated and 179 downregulated genes were identified. Thirty transcription factors able to target the differentially expressed genes were predicted and selected based on public databases. One hundred seventeen overlapping genes were identified from the differentially expressed genes and the miRNAs predicted by miRWalk. Furthermore, NF-κB/IL6, PTGS2, MYC/hsa-miR-574-5p, hsa-miR-26b-5p, hsa-miR-335-5p, and hsa-miR-98-5p, which are involved in the transcription factor-miRNA-mRNA coregulation network, were found to be associated with meningioma.

Conclusion

The bioinformatics analysis identified several potential molecules and relevant pathways that may represent critical mechanisms involved in the progression and development of meningioma. This work provides new insights into meningioma pathogenesis and treatments.

Meningioma-like Tumor of the Skin Revisited: A Distinct CD34+ Dermal Tumor With an Expanded Histologic Spectrum

The term meningioma-like tumor of the skin (MLTS) was coined in 1993 to designate a particular whorled spindle cell superficial cutaneous tumor. No additional confirmed cases of this entity have been reported to date. Some authors have speculated that these cases might be cellular neurothekeomas. In order to delineate the histologic spectrum and the immunophenotype of this unusual tumor, we studied 5 cases, 2 previously unreported and the 3 original cases. The immunohistochemical findings of case 5, however, were limited to those from the original study. Clinically, the tumor presented as a reddish papule, plaque, or nodule, located in the extremities or trunk. The patient often referred to a recent growth of a longstanding lesion. Histologically, the characteristic whorled spindle and stellate dendritic cell population, commonly in a perivascular arrangement, and variable myxoid component, were consistently found in all cases. A prominent microvasculature was also a constant finding. The presence of large deciduoid cells was conspicuous in one case. A reticular pattern of multivacuolated cells giving a chordoma-like appearance was evident in another case. Tumor cells were diffusely positive for CD34 in all 4 cases studied, and negative for S-100, EMA, NKI-C3, CD68, and smooth muscle markers. No complete loss of retinoblastoma protein was found. No brachyury immunostaining was found in the case with chordoid features. No EWSR1 or NAB2-STAT6 gene fusions were found. From these findings, we demonstrate that MLTS is a distinct CD34 spindle cell benign dermal tumor, unrelated to cellular neurothekeoma, and exhibiting myxoid, deciduoid, or chordoma-like features.

Histological Grade of Meningioma: Prediction by Intravoxel Incoherent Motion Histogram Parameters

RATIONALE AND OBJECTIVES

To evaluate the usefulness of intravoxel incoherent motion (IVIM) histogram analysis for differentiating low-grade meningiomas (LGMs) and high-grade meningiomas (HGMs).

MATERIALS AND METHODS

Fifty-nine patients with pathologically confirmed meningiomas (45 LGMs and 14 HGMs) underwent IVIM MR imaging. Maps of IVIM parameters (perfusion fraction, f; true diffusion coefficient, D; and pseudo diffusion coefficient, D*), as well as of the apparent diffusion coefficient (ADC), were generated. Histogram analysis was performed using parametric values from all voxels in regions-of-interest manually drawn to encompass the whole tumor. The histogram results of ADC and IVIM parameters were compared using the Mann-Whitney U test. Area under the receiver operating characteristic curve (AUC) values were generated to evaluate how well each parameter could differentiate LGMs from HGMs. Spearman's rank correlation coefficients were used to evaluate correlations between histogram parameters and Ki-67 expression.

RESULTS

Compared to LGM, HGM showed significantly higher standard deviation (SD), variance, and coefficient of variation (CV) of ADC (p< 0.006-0.028; AUC, 0.693-0.748), D (p< 0.004-0.032; AUC, 0.670-0.752), and significantly higher CV of f (p< 0.005-0.024; AUC = 0.737). Means and percentiles of ADC and IVIM parameters did not differ significantly between LGM and HGM. Significant positive correlations were identified between Ki-67 and histogram parameters of ADC (SD, variance, kurtosis, skewness, and CV) and D (SD, variance, kurtosis, and CV), whereas no significant correlation with Ki-67 was shown for mean or percentiles of ADC and IVIM parameters.

CONCLUSION

Heterogeneity histogram parameters of ADC, D, and f may be useful for differentiating LGMs from HGMs.

The correlation of fractional anisotropy parameters with Ki-67 index, and the clinical implication in grading of non-enhancing gliomas and neuronal-glial tumors

PURPOSE

To investigate the correlation between the FA parameters and Ki-67 labeling index, and their diagnostic performance in grading supratentorial non-enhancing gliomas and neuronal-glial tumors (GNGT).

METHODS

This institutional review board-approved, Health Insurance Portability and Accountability (HIPAA) compliant retrospective study enrolled 35 patients, including 19 with low grade GNGT and 16 with high grade GNGT. The mean FA, maximal FA and mean maximal FA values derived from diffusion tensor imaging were measured. The correlation between the FA parameters and the Ki-67 labeling index was assessed by Spearman rank test. The receiver operating characteristic curve analysis and multivariate logistic regression analysis were performed to detect the optimal imaging parameters in grading GNGT.

RESULTS

The three FA parameters of low grade GNGT were significantly lower than the high grade GNGT (p < 0.001). The mean FA, maximal FA and mean maximal FA had significant positive correlation with Ki-67 labeling index (p = 0.001, p < 0.001, p < 0.001 respectively). The maximal FA showed a higher sensitivity and specificity in grading of non-enhancing GNGT with specificity of 78.9%, sensitivity of 100.0%, respectively.

CONCLUSIONS

The FA parameters correlated with Ki-67 labeling index, and were useful surrogates in preoperative grading supratentorial non-enhancing GNGT.

A case report of resected ectopic malignant meningioma with lung metastasis

INTRODUCTION

Meningioma is mostly a benign tumor, but sometimes it is malignant, and there have been reports of distant metastases.

PATIENT CONCERNS

The patient, a woman in her 40s, was under follow-up after resection of an ectopic malignant meningioma originating in the left axilla. She was referred to our department because of a nodule shadow in the right lung on chest computed tomography (CT) 3 years and 5 months postoperatively.

DIAGNOSIS

Chest CT showed a 1.0 cm nodule shadow in the right S4, which was positive on positron emission tomography-CT; no abnormality was found in any other organ. Therefore, it was considered to be a metastatic lung tumor.

INTERVENTIONS

Right middle lobe partial resection was performed using thoracoscopic surgery, and a diagnosis of pulmonary metastasis of ectopic malignant meningioma was made by histopathology and immunohistochemistry.

OUTCOMES

In this case, complete resection was possible.

CONCLUSION

Meningioma occurs mainly in the cranium, and occurrence in the soft tissue of the extremities is extremely rare. To our knowledge, ours is the first report of a histologically malignant ectopic meningioma with metastasis to the thoracic cavity.

Array expression meta-analysis of cancer stem cell genes identifies upregulation of PODXL especially in DCC low expression meningiomas

BACKGROUND

Meningiomas are the most common intracranial tumors, with a subset of cases bearing a progressive phenotype. The DCC netrin 1 receptor (DCC) is a candidate gene for early meningioma progression. Cancer stem cell (CSC) genes are emerging as cancer therapeutic targets, as their expression is frequently associated with aggressive tumor phenotypes. The main objective of the study was to identify deregulated CSC genes in meningiomas.

MATERIALS AND METHODS

Interrogating two expression data repositories, significantly differentially expressed genes (DEGs) were determined using DCC low vs. DCC high expression groups and WHO grade I (GI) vs. grade II + grade III (GII + GIII) comparison groups. Human stem cell (SC) genes were compiled from two published data sets and were extracted from the DEG lists. Biofunctional analysis was performed to assess associations between genes or molecules.

RESULTS

In the DCC low vs. DCC high expression groups, we assessed seven studies representing each between seven and 58 samples. The type I transmembrane protein podocalyxin like (PODXL) was markedly upregulated in DCC low expression meningiomas in six studies. Other CSC genes repeatedly deregulated included, e.g., BMP/retinoic acid inducible neural specific 1 (BRINP1), prominin 1 (PROM1), solute carrier family 24 member 3 (SLC24A3), rRho GTPase activating protein 28 (ARHGAP28), Kruppel like factor 5 (KLF5), and leucine rich repeat containing G protein-coupled receptor 4 (LGR4). In the GI vs. GII + GIII comparison groups, we assessed six studies representing each between nine and 68 samples. DNA topoisomerase 2-alpha (TOP2A) was markedly upregulated in GII + GIII meningiomas in four studies. Other CSC genes repeatedly deregulated included, e.g., ARHGAP28 and PODXL. Network analysis revealed associations of molecules with, e.g., cellular development and movement; nervous system development and function; and cancer.

CONCLUSIONS

This meta-analysis on meningiomas identified a comprehensive list of deregulated CSC genes across different array expression studies. Especially, PODXL is of interest for functional assessment in progressive meningiomas.

[Use of the PELICAN software for the creation and export of standardized pathology reports in central nervous system tumors: Example of meningiomas]

INTRODUCTION

PELICAN ("Partager Efficacement en Laboratoire les Informations des Comptes rendus ANatomopathologiques") is a software, which generates standardized reports, and allows to automatically create a database. It has been used in central nervous system tumor pathology at the University Hospital of Nancy since 2014. The purpose of this article was to illustrate the use of this application for meningiomas, with a first statistical evaluation.

MATERIALS AND METHODS

The export of data included all cases of meningiomas recorded in the PELICAN application until July 2018. The PELICAN application is a Microsoft Excel file containing a software, written in Visual Basic for Applications, and used by the pathologist to create the report. The main clinical data were collected from the Hérault Register census form. Follow-up was systematically reported for atypical meningiomas.

RESULTS

Two hundred and ninety-five meningiomas were analyzed, including 250 grade I meningiomas, 42 grade II meningiomas, and 3 grade III meningiomas. Grade II meningiomas were characterized by a significantly higher proportion of men (P=0.002) and dural infiltration (P<0.001), a significant increase in the Ki-67 index (P<0.0001), and a significant decrease in progesterone receptor expression (P<0.001). In atypical meningiomas, a Ki-67 index of more than 20 % was significantly correlated with a shorter progression-free survival (P=0.032).

CONCLUSION

The PELICAN software is an easy-to-use tool that allows to generate standardized reports and feed a database, opening very interesting perspectives from an epidemiological and scientific point of view.

CORRELATION OF PERITUMORAL BRAIN EDEMA WITH MORPHOLOGICAL CHARACTERISTICS AND KI67 PROLIFERATIVE INDEX IN RESECTED INTRACRANIAL MENINGIOMAS

The aim of the study was to analyze correlation between morphological characteristics of intracranial meningiomas and Ki67 labeling index (Ki67 LI), and their influence on peritumoral brain edema (PTBE). There were 41 consecutive patients with intracranial meningiomas surgically treated at the Department of Neurosurgery, Zenica Cantonal Hospital, Zenica, Bosnia and Herzegovina, during the period from January 2010 to December 2015. We reviewed clinical data including patient age, gender, magnetic resonance imaging (MRI) characteristics of the tumor and peritumoral edema, tumor margins, intraoperative characteristics, histopathologic grade and Ki67 LI. In all cases, follow up MRI was obtained at about three months after resection and PTBE was analyzed. Our research showed the tumor volume, tumor margins, and intraoperative signs of arachnoidal and pial invasion to be associated with PTBE in intracranial meningiomas. Ki67 LI expression correlated with PTBE. This study showed the resolution of PTBE to depend on invasive behavior of meningioma and KI67 LI. PTBE, pial/cortical and arachnoidal invasion significantly influence the extent of surgical resection.

Factors Associated With Meningioma Detected in a Population-Based Sample

OBJECTIVE

To determine the frequency of incidental meningioma and identify associated factors in a population-based sample of participants who systematically underwent brain imaging.

PATIENTS AND METHODS

We searched the Mayo Clinic Study of Aging, a population-based sample of Olmsted County, Minnesota, residents who underwent longitudinal magnetic resonance imaging of the brain. Using a text search of radiologists' notes for 2402 individuals (median age, 75.0 years) who underwent imaging between August 10, 2005, and July 31, 2014, we identified 52 patients (2.2%) who had at least one meningioma. We estimated the association of selected risk factors with the presence of meningioma using odds ratios and 95% CIs from logistic regression models adjusted for age and sex. Based on these results, we moved the most significant variables forward to a multivariable model.

RESULTS

Controlling for age and sex, significant associations with the presence of meningioma included higher body mass index (odds ratio [OR], 1.06; 95% CI, 1.01-1.12; P=.03), nonsteroidal anti-inflammatory drugs (OR, 2.11; 95% CI, 1.13-3.95; P=.02), aspirin (OR, 1.90; 95% CI, 1.05-3.46; P=.04), and blood pressure-lowering medication (OR, 2.06; 95% CI, 1.06-3.99; P=.03). Lower risk was associated with male sex (OR, 0.51; 95% CI, 0.29-0.90; P=.02), coronary artery disease (OR, 0.46; 95% CI, 0.22-0.97; P=.04), and higher self-reported anxiety (OR, 0.88; 95% CI, 0.78-0.98; P=.02). Simultaneous adjustment for all of these factors except aspirin in a multivariable model did not attenuate these associations (concordance, 0.71).

CONCLUSION

In a population-based sample of 2402 participants, 52 (2.2%) had an incidental meningioma. They were more likely to be female and have higher body mass index. Meningioma was also associated with certain medications (nonsteroidal anti-inflammatory drugs and blood pressure-lowering medications) and inversely with anxiety and coronary artery disease.

Severe headache in a patient with meningioma showing extensive dural tail correlates with IgG4-positive plasma cells and eosinophils: A case report and review of literature

Background

Meningiomas originate from meningothelial cells of the arachnoid membrane. Few cases of meningioma with infiltration of inflammatory cells, such as lymphocytes and plasma cells, have been reported, and the mechanisms underlying meningioma-induced inflammatory reactions have not been fully elucidated.

Case Description

In this study, we report an extremely rare case of meningioma with infiltration of both IgG4-positive plasma cells and eosinophils showing extensive dural tail and reactive inflammation of the surrounding arachnoid tissue. The main clinical manifestation was a severe headache, which was improved by surgical excision of the tumor.

Conclusion

Only 8 cases of meningioma with IgG4-positive plasma cells have been reported, and only one case exhibited eosinophil infiltration. IgG4-related inflammatory response might mediate inflammation in surrounding tissue, resulting in thickening of the dura adjacent to a meningioma and severe headache. The mechanisms underlying inflammation by meningiomas require further investigation.

Progesterone Receptor Is Responsible for Benign Biology of Skull Base Meningioma

OBJECTIVE

Many studies have been performed to evaluate the roles of estrogen receptor and progesterone receptor (PGR) in meningiomas, but their influence on tumor behavior remains unclear.

METHODS

We retrospectively analyzed patients with meningioma who underwent surgical resection at our institute. Patients with data for immunohistochemical staining of estrogen receptor, PGR, and Ki-67 were included.

RESULTS

The study included 161 patients comprising 61 skull base and 100 non-skull base meningiomas. Histologically, the number of patients with World Health Organization (WHO) grade I, II, and III disease were 132 (82.0%), 22 (14.7%), and 7 (4.4%), respectively. Tumor recurrence was observed in 21 (13.0%). Negative PGR, high Ki-67 index, incomplete resection, and WHO grade II or III were significantly correlated with tumor recurrence and shorter recurrence-free survival. Skull base meningiomas were difficult to remove entirely; 31 patients (50.8%) with skull base and 77 patients (77.0%) with non-skull base meningiomas had overall complete removal (P = 0.0006). Ki-67 indices, proportion of WHO grade II or III, and recurrence rate or recurrence-free survival did not differ between the tumor locations. The only difference was the proportion of patients with positive PGR, which was significantly higher for skull base meningiomas (61.5 ± 33.4% vs. 42.2 ± 35.7%, P = 0.0009).

CONCLUSIONS

Although skull base meningiomas are often incompletely resected, there were no differences in recurrence-free survival or recurrence rate between skull base and non-skull base meningiomas. As the Ki-67 index and WHO grade were not different between these locations, the high rate of positive PGR may be responsible for the benign biology of skull base meningiomas.

Molecular progression in unusual recurrent non-pediatric intracranial clear cell meningioma

We report a case of a recurrent clear cell meningioma (ccm) in the frontal lobe of the brain of a 67-year-old man. The patient developed three recurrences: at 3, 10, and 12 years after his initial surgery. Histopathology observations revealed a grade 2 ccm with positivity for vimentin and epithelial membrane antigen. Expression of E-cadherin was positive only in the primary tumour and in the first available recurrence. Fluorescence in situ hybridization analyses demonstrated 1p and 14q deletions within the last recurrence. Multiplex ligation-dependent probe amplification studies revealed a heterozygous partial NF2 gene deletion, which progressed to total loss in the last recurrence. The last recurrence showed homozygous deletions in CDKN2A and CDKN2B. The RASSF1 gene was hypermethylated during tumour evolution. In this report, we show the genetic alterations of a primary ccm and its recurrences to elucidate their relationships with the changes involved in the progression of this rare neoplasm.

Meningioma mimics: five key imaging features to differentiate them from meningiomas

There are a wide variety of intracranial mass lesions, both benign and malignant, which can closely mimic meningioma on imaging. We present five characteristic imaging features that can alert the radiologist to consider other differential diagnoses. Of the five imaging characteristics that were rarely seen in meningiomas, but common and specific for meningioma mimics, absence of dural tail is the most common (83.7%). Homogeneous T2 hyperintensity or T2 hypointensity are seen in nearly half of meningioma mimics and osseous destruction and leptomeningeal extension are present in 40.5% and 21.6% of meningioma mimics, respectively. The distinction between meningioma and its mimics is important because a large portion of the meningioma mimics requires substantially different clinical and surgical management.

Simultaneous analysis of miRNA-mRNA in human meningiomas by integrating transcriptome: A relationship between PTX3 and miR-29c

BACKGROUND

Although meningioma is a common disease, there is a lack of understanding of the underlying molecular mechanisms behind its initiation and progression. We used combined miRNA-mRNA transcriptome analysis to discover dysregulated genes and networks in meningiomas.

METHODS

Fourteen fresh-frozen meningioma samples and one human meningeal cell line were analyzed by using miRNA and whole transcriptome microarray chips. Data was filtered and analyzed. Candidate miRNAs and mRNAs were selected for validation in fifty-eight patient samples. miRNA and target mRNA relationships were assessed by inhibiting miRNA in meningioma cells. Apoptosis and viability assays were also used as functional tests.

RESULTS

With the whole transcriptome microarray, 3753 genes were found to be dysregulated, and 891 miRNAs were found to be dysregulated as a result of miRNA microarray. Results were combined and analyzed with bioinformatics tools. Top differential pathways included those of inflammation, cancer, and cellular growth and survival. The oncosupressor PTX3 was constitutively low in meningioma samples. Moreover, PTX3 negatively correlated with miR-29c in our samples. Inhibiting miR-29c upregulated the PTX3 level, induced apoptosis of meningioma cells, and decreased cell viability. CABIN1, miR-29c, TMOD1, PTX3, RPL22, SPARCL1 and RELA were correlated with clinicopathological features in patient samples.

CONCLUSIONS

Our results present the first integrated mRNA-miRNA analysis in meningiomas. miR-29c-3p and PTX3 are inversely correlated in tissues and meningioma cells, hinting that PTX3 can be regulated by miR-29c-3p. Furthermore, we determined potential clinicopathological markers.

Optimizing gDNA extraction from fresh frozen meningioma tissue for downstream genetic analysis

OBJECTIVE

Meningioma is the most common brain tumor. Genetic mutations in meningioma that include deletion of the neurofibromatosis type 2 gene, (NF2), offer diagnostic information on tumor behavior, recurrence and potential response to treatment. Obtaining high-grade genetic material is critical for accurate, sensitive and robust molecular testing. Currently, no standardized procedure exists for extracting gDNA from meningioma, and this problem was addressed in this report.

METHOD

This study compared the yield and quality of extracted gDNA from patient meningioma specimens using an optimized phenol chloroform method and two commercial silica column-based extractions kits and tested respective performances as template in qPCR tests and multiplex ligation-dependent probe amplification (MLPA) NF2 screening.

RESULTS

Mean gDNA yields were comparable for each method tested; however, phenol chloroform extraction outperformed column-based kits in all other quality assurance metrics examined. Phenol chloroform extracted gDNA was highly pure, and of a higher fragment size species when compared to column prepared gDNA. qPCR of GAPDH, B2MG, and RPL37A housekeeping genes demonstrated variance in cycle thresholds between patient samples was much lower in the phenol chloroform group. Similarly, primer efficiencies were significantly improved in this sample group which translated to a broader qPCR linear dynamic range and much improved qPCR performance at low concentrations of template. MLPA screening identified NF2 gene deletions in 6 of 12 meningioma samples. Inconsistencies in copy number data for NF2 and reference regions of the genome were observed between gDNA sample extraction groups that included both false negative and positive errors in silica column derived gDNA samples.

CONCLUSIONS

This study outlines a highly robust phenol chloroform extraction method for obtaining high-quality gDNA from frozen meningioma tissue and highlights the significance of performing adequate quality assurance when using gDNA for downstream genetic analysis. Most importantly, we demonstrate using gDNA extracted with silica column based kits can lead to diagnostic errors when screening NF2 deletions in meningiomas with MLPA.

An Overview of Anterior Skull Base Meningiomas and the Endoscopic Endonasal Approach

Meningiomas represent 30% of all primary brain tumors. Anterior skull base meningiomas represent 8.8% of all meningiomas. Surgical resection is a main treatment option for tumors that are symptomatic and/or growing. Recurrence is directly related to the extent of resection of the tumor, the dural attachment, and pathologic bone. Endoscopic endonasal approaches represent an important addition to the treatment armamentarium for skull base meningiomas. This article provides an overview of meningiomas, with a focus on those of the anterior skull base and their management.

Molecular Genetics of Intracranial Meningiomas with Emphasis on Canonical Wnt Signalling

Research over the last decade recognized the importance of novel molecular pathways in pathogenesis of intracranial meningiomas. In this review, we focus on human brain tumours meningiomas and the involvement of Wnt signalling pathway genes and proteins in this common brain tumour, describing their known functional effects. Meningiomas originate from the meningeal layers of the brain and the spinal cord. Most meningiomas have benign clinical behaviour and are classified as grade I by World Health Organization (WHO). However, up to 20% histologically classified as atypical (grade II) or anaplastic (grade III) are associated with higher recurrent rate and have overall less favourable clinical outcome. Recently, there is emerging evidence that multiple signalling pathways including Wnt pathway contribute to the formation and growth of meningiomas. In the review we present the synopsis on meningioma histopathology and genetics and discuss our research regarding Wnt in meningioma. Epithelial-to-mesenchymal transition, a process in which Wnt signalling plays an important role, is shortly discussed.

Pathologic aspects of skull base tumors

Skull base tumors form a highly heterogeneous group. As there are several structures in this anatomical site, a large number of different primary malignancies might develop, as well as a variety of secondary (metastatic) tumors. In this article, the most common malignancies are presented, along with a short histopathologic description. For some entities, an immunohistochemical profile is also given that should be helpful in proper diagnosis. As many pathologic diagnoses nowadays also include genetic studies, the most common genetic abnormalities in skull base tumors are presented.

The role of MAPK signaling pathway in the Her-2-positive meningiomas

Meningiomas are common types of adult nerve system tumors. Although most cases are considered benign, due to its high rate of recurrence and easy malignant progression to anaplastic meningioma they present a puzzle for the current treatment. The HER-2 oncogene has important value for meningioma cells development and progression. So far, little is known about the effect on the exact underlying signal pathway and molecular mechanisms of HER-2-positive meningioma cells. The goal of the present study was to determine the effects of HER-2 gene and possible involvement of MAPK signal pathway in human malignant meningioma. We applied q-PCR analysis, immunofluorescence (IF) staining, western blot analysis, animal model, MAPK inhibition, MTT assay and cell invasion analysis for the investigation. The results demonstrated that the downregulation of the expression of HER-2 significantly inhibited cell motility and proliferation of human meningioma cells in vivo. Accordingly, in the HER-2-overexpression meningioma cells with the inhibition of ERK1/2, ERK5, JNK, in the cells with the ERK1/2, ERK5 inhibition, protein expression was markedly suppressed as well as the cell proliferation resistance. No difference was observed in the HER-2-overexpression meningioma cells with the inhibition of JNK. These findings suggest that HER-2 gene can affect the proliferation ability of human meningioma cells in vivo and MAPK signal pathway may contribute to the carcinogenesis and development of human meningiomas combinating with HER-2.

Microarray Expression Data Identify DCC as a Candidate Gene for Early Meningioma Progression

Meningiomas are the most common primary brain tumors bearing in a minority of cases an aggressive phenotype. Although meningiomas are stratified according to their histology and clinical behavior, the underlying molecular genetics predicting aggressiveness are not thoroughly understood. We performed whole transcript expression profiling in 10 grade I and four grade II meningiomas, three of which invaded the brain. Microarray expression analysis identified deleted in colorectal cancer (DCC) as a differentially expressed gene (DEG) enabling us to cluster meningiomas into DCC low expression (3 grade I and 3 grade II tumors), DCC medium expression (2 grade I and 1 grade II tumors), and DCC high expression (5 grade I tumors) groups. Comparison between the DCC low expression and DCC high expression groups resulted in 416 DEGs (p-value<0.05; fold change>2). The most significantly downregulated genes in the DCC low expression group comprised DCC, phosphodiesterase 1C (PDE1C), calmodulin-dependent 70kDa olfactomedin 2 (OLFM2), glutathione S-transferase mu 5 (GSTM5), phosphotyrosine interaction domain containing 1 (PID1), sema domain, transmembrane domain (TM) and cytoplasmic domain, (semaphorin) 6D (SEMA6D), and indolethylamine N-methyltransferase (INMT). The most significantly upregulated genes comprised chromosome 5 open reading frame 63 (C5orf63), homeodomain interacting protein kinase 2 (HIPK2), and basic helix-loop-helix family, member e40 (BHLHE40). Biofunctional analysis identified as predicted top upstream regulators beta-estradiol, TGFB1, Tgf beta complex, LY294002, and dexamethasone and as predicted top regulator effectors NFkB, PIK3R1, and CREBBP. The microarray expression data served also for a comparison between meningiomas from female and male patients and for a comparison between brain invasive and non-invasive meningiomas resulting in a number of significant DEGs and related biofunctions. In conclusion, based on its expression levels, DCC may constitute a valid biomarker to identify those benign meningiomas at risk for progression.

Update on Select Benign Mesenchymal and Meningothelial Sinonasal Tract Lesions

Several benign and malignant mesenchymal and meningothelial lesions may preferentially affect or extend into the sinonasal tract. Glomangiopericytoma (GPC, formerly sinonasal-type hemangiopericytoma) is a specific tumor with a predilection to the sinonasal tract. Sinonasal tract polyps with stromal atypia (antrochoanal polyp) demonstrate unique histologic findings in the sinonasal tract. Juvenile nasopharyngeal angiofibroma (JNA) arises from specialized tissue in this location. Meningioma may develop as direct extension from its intracranial counterpart or as an ectopic tumor. Selected benign mesenchymal tumors may arise in the sinonasal tract and pose a unique differential diagnostic consideration, such as solitary fibrous tumor and GPC or lobular capillary hemangioma and JNA. Although benign and malignant vascular, fibrous, fatty, skeletal muscle, and nerve sheath tumors may occur in this location, this paper focuses on a highly select group of rare benign sinonasal tract tumors with their clinicopathological and molecular findings, and differential diagnosis.