Related mechanisms, current treatments, and new perspectives in meningioma

Meningiomas are non-glial tumors that are the most common primary brain tumors in adults. Although meningioma can possibly be cured with surgical excision, variations in atypical/anaplastic meningioma have a high recurrence rate and a poor prognosis. As a result, it is critical to develop novel therapeutic options for high-grade meningiomas. This review highlights the current histology of meningiomas, prevalent genetic and molecular changes, and the most extensively researched signaling pathways and therapies in meningiomas. It also reviews current clinical studies and novel meningioma treatments, including immunotherapy, microRNAs, cancer stem cell methods, and targeted interventions within the glycolysis pathway. Through the examination of the complex landscape of meningioma biology and the highlighting of promising therapeutic pathways, this review opens the way for future research efforts aimed at improving patient outcomes in this prevalent intracranial tumor entity.

Primary Intraparenchymal Meningiomas: A Case Report and a Systematic Review

BACKGROUND

Primary intraparenchymal meningiomas are exceedingly rare and often challenging to diagnose, given their misleading radiologic features. It is hypothesized that they arise from the cap cells of the pia mater that enter the brain via penetrating blood vessels during brain development. We systematically reviewed and analyzed previously reported features of primary intraparenchymal meningiomas in terms of radiography, presenting symptoms, and histopathology.

METHODS

A literature search of the Web of Science and PubMed databases and crossed references was performed in March 2021, per PRISMA guidelines, with no restrictions regarding publication date. Data regarding demographic features, clinical, radiographic, and histopathologic characteristics were extracted.

RESULTS

A total of 52 patients (including the reported case) were included in this review. The mean age was 21.1 years (range, 0.3-66 years) with a male/female ratio of 1.9:1. The most common localizations of intraparenchymal meningiomas were in the frontal (30.8%) and temporal (21.2%) lobes. Cyst formation was more readily observed and was noted in 51.4% of patients. Histopathology showed a higher incidence of World Health Organization grade II (14/52, 26.9%) and World Health Organization grade III (7/52, 13.5%) of primary intraparenchymal meningiomas.

CONCLUSIONS

We present a comprehensive analysis of every reported primary intraparenchymal meningioma. Because of their rarity and capacity to mimic other more common intra-axial tumors, they represent a diagnostic challenge. This systematic review highlights the importance of paying attention to atypical intra-axial lesions, with a particular reflection on the discrepancy between clinical characteristics and imaging features.

Combined 68Ga-NOTA-PRGD2 and 18F-FDG PET/CT Can Discriminate Uncommon Meningioma Mimicking High-Grade Glioma

OBJECTIVES

Uncommon pathological subtypes of meningioma may present with severe peritumoral brain edema and mimic high-grade glioma (HGG). In a prospective cohort study of Ga-NOTA-PRGD2 PET/CT to evaluate glioma, we occasionally observed that a combination of Ga-NOTA-PRGD2 and F-FDG was able to differentiate these 2 lesion types.

METHODS

From 2013 to 2016, 21 patients suspected of HGG by MRI were recruited for evaluation using Ga-NOTA-PRGD2 PET/CT. Brain F-FDG PET/CT was performed within 3 days for comparison, and the tumor was surgically removed. The PET results were compared with integrin αvβ3 expression and microvascular density quantification of tumor samples.

RESULTS

Of the 21 recruited patients, 5 patients were finally pathologically diagnosed as uncommon meningioma with severe peritumoral brain edema, including chordoid meningioma (n = 1), angiomatous meningioma (n = 1), and mixed angiomatous and microcystic meningioma (n = 3). Sixteen were diagnosed as HGG. All the meningioma lesions (n = 5) exhibited intense and homogeneous Ga-NOTA-PRGD2 uptake with higher SUVmax on Ga-NOTA-PRGD2 PET (1.64-7.86; mean ± SD, 4.23 ± 2.48) than the HGG lesions (0.81-2.99; mean ± SD, 1.57 ± 0.33; P = 0.0047). Moreover, the uptake ratios of Ga-NOTA-PRGD2 over F-FDG, normalized as lg100 * SUVmax (RGD / FDG), in the uncommon meningiomas were significantly higher than those in HGG (1.87 ± 1.36 vs 1.04 ± 0.87, P = 0.0001). A cutoff value of 1.58 was able to discriminate between these lesion types. There were positive correlations among the expression level of integrin αvβ3, microvascular density, and the tumor-to-background ratio derived from Ga-NOTA-PRGD2 PET (P < 0.05).

CONCLUSIONS

This study reveals a specific imaging pattern of uncommon meningioma mimicking HGG, in which Ga-NOTA-PRGD2 PET provided added value to F-FDG PET.

Rare Parenchyma Meningioma in an Adolescent Female With Cheek Tingling: A Case Report

The following is a report on a rare parenchyma meningioma and the computed tomography (CT) and magnetic resonance imaging (MRI) findings. To our knowledge, this was the first characterization of magnetic resonance spectroscopy (MRS) in a parenchyma meningioma. Three days after initial presentation, a 14-year-old female student reported feeling tingling in her cheek, grading 3 to 4 points. Two hours later, the tingling had disappeared. The patient was admitted to hospital with stable vital signs and no abnormal presentations upon physical examination. A routine CT scan of the brain showed a quasicircular region of the left occipital lobe was homogenous hyperdense and an arcualia calcification was found on the lesion's margin and the boundary was ill-defined. Further MRI and contrast-enhanced scanning of the brain showed that a lobulated nidus with abnormal signaling was present in the left occipital lobe and was approximately 1.9 × 2.0 cm. Hypointensity on T1-weighted imaging and a slight hyperintensity on T2-weighted imaging was also observed. A short T2 signal appeared on the margin and a few longer T2 edema zones appeared around the nidus, whereas the lesion showed homogenous enhancement. MRS was characterized by a slight or moderate increase of a choline (Cho) peak and a small reduction of the N-acetyl aspartate (NAA) peak. After completing the preoperative preparation, the excision of the supratentorial deep lesions was performed on the patient. The pathology led to a diagnosis of a left occipital lobe meningioma, WHO I. The patient was followed-up for 14 months postoperation, and had no reoccurrences. Intraparenchymal meningioma rarely occurs in brain parenchyma, and is characterized by lesions with abundant blood supply and requires a glioma to be identified. MRS is a potential tool for preoperative diagnosis of intraparenchymal meningioma.

Predictors of recurrence in the management of chordoid meningioma

Management of chordoid meningiomas (CMs) is complicated by high rates of recurrence, particularly following subtotal resection. Optimal management is not established given the paucity of published experience. To identify prognostic factors for recurrence following resection, the authors conducted the largest systematic review of CMs to date. A comprehensive search on MEDLINE (OVID and Pubmed), Scopus, Embase, and Web of Science utilizing the search terms "chordoid" AND "meningioma" was performed to identify all reports of pathologically confirmed intracranial CMs. A total of 221 patients were included, comprising 120 females and 101 males. Mean age, MIB-1/Ki67, and tumor size was 45.5 years, 4.3% (range 0.1-26.6%), and 4.1 cm (range 0.8-10 cm), respectively. 5-, and 10- year progression free survival was 67.5 and 54.4%, respectively. Gross total resection (GTR) and subtotal resection was achieved in 172 and 48 patients, respectively. Adjuvant radiotherapy (RT) was given to 30 patients. Multivariate analysis found GTR was strongly correlated with decreased recurrence rates (HR 0.04, p = <0.0001), while higher MIB-1 labeling index (≥5 vs <5%) was associated with increased recurrence (HR 7.08; p = 0.016). Adjuvant RT, age, gender, and tumor location were not associated with recurrence. GTR resection is the strongest predictor of tumor control, and should be the goal to minimize local progression. Additionally, higher MIB-1 labeling was associated with increased rates of tumor recurrence. Tumors that are subtotally resected or demonstrate higher MIB-1 are at greater recurrence and warrant consideration for RT and close long term follow up.

[Chordoma]

PURPOSES

To review in the literature, all the epidemiological, clinical, radiological, histological and therapeutic data regarding chordomas as well as various notochordal entities: ecchordosis physaliphora, intradural and intraparenchymatous chordomas, benign notochordal cell tumors, parachordomas and extra-axial chordomas. To identify different types of chordomas, including familial forms, associations with tuberous sclerosis, Ollier's disease and Maffucci's syndrome, forms with metastasis and seeding. To assess the recent data regarding molecular biology and progress in targeted therapy. To compare the different types of radiotherapy, especially protontherapy and their therapeutic effects. To review the largest series of chordomas in their different localizations (skull base, sacrum and mobile spine) from the literature.

MATERIALS

The series of 136 chordomas treated and followed up over 20 years (1972-2012) in the department of neurosurgery at Lariboisière hospital is reviewed. It includes: 58 chordomas of the skull base, 47 of the craniocervical junction, 23 of the cervical spine and 8 from the lombosacral region. Similarly, 31 chordomas in children (less than 18 years of age), observed in the departments of neurosurgery of les Enfants-Malades and Lariboisière hospitals, are presented. They were observed between 1976 and 2010 and were located intracranially (n=22 including 13 with cervical extension), 4 at the craniocervical junction level and 5 in the cervical spine.

METHODS

In the entire Lariboisière series and in the different groups of localization, different parameters were analyzed: the delay of diagnosis, of follow-up, of occurrence of metastasis, recurrence and death, the number of primary patients and patients referred to us after progression or recurrence and the number of deaths, recurrences and metastases. The influence of the quality of resection (total, subtotal and partial) on the prognosis is also presented. Kaplan-Meier actuarial curves of overall survival and disease free survival were performed in the entire series, including the different groups of localization based on the following 4 parameters: age, primary and secondary patients, quality of resection and protontherapy. In the pediatric series, a similar analysis was carried-out but was limited by the small number of patients in the subgroups.

RESULTS

In the Lariboisière series, the mean delay of diagnosis is 10 months and the mean follow-up is 80 months in each group. The delay before recurrence, metastasis and death is always better for the skull base chordomas and worse for those of the craniocervical junction, which have similar results to those of the cervical spine. Similar figures were observed as regards the number of deaths, metastases and recurrences. Quality of resection is the major factor of prognosis with 20.5 % of deaths and 28 % of recurrences after total resection as compared to 52.5 % and 47.5 % after subtotal resection. This is still more obvious in the group of skull base chordomas. Adding protontherapy to a total resection can still improve the results but there is no change after subtotal resection. The actuarial curve of overall survival shows a clear cut in the slope with some chordomas having a fast evolution towards recurrence and death in less than 4 years and others having a long survival of sometimes more than 20 years. Also, age has no influence on the prognosis. In primary patients, disease free survival is better than in secondary patients but not in overall survival. Protontherapy only improves the overall survival in the entire series and in the skull base group. Total resection improves both the overall and disease free survival in each group. Finally, the adjunct of protontherapy after total resection is clearly demonstrated. In the pediatric series, the median follow-up is 5.7 years. Overall survival and disease free survival are respectively 63 % and 54.3 %. Factors of prognosis are the histological type (atypical forms), localization (worse for the cervical spine and better for the clivus) and again it will depend on the quality of resection.

CONCLUSIONS

Many different pathologies derived from the notochord can be observed: some are remnants, some may be precursors of chordomas and some have similar features but are probably not genuine chordomas. To-day, immuno-histological studies should permit to differentiate them from real chordomas. Improving knowledge of molecular biology raises hopes for complementary treatments but to date the quality of surgical resection is still the main factor of prognosis. Complementary protontherapy seems useful, especially in skull base chordomas, which have better overall results than those of the craniocervical junction and of the cervical spine. However, we are still lacking an intrinsic marker of evolution to differentiate the slow growing chordomas with an indolent evolution from aggressive types leading rapidly to recurrence and death on which more aggressive treatments should be applied.