Angiomatous Meningiomas Have a Very Benign Outcome Despite Frequent Peritumoral Edema at Onset

A Meningioma With Extensive Peritumoral Edema Mimicking Metastatic Brain Tumor: A Case Report

Meningioma is the most common brain tumor among all histologically reported malignant and non-malignant tumors of the central nervous system. Angiomatous meningioma is one of the subtypes of meningioma that is rarely reported. In this paper, we present a case of a 67-year-old female patient who sought consultation due to seizure, cognitive decline, and parkinsonism. Contrast-enhanced MRI showed a well-defined tumor in the left frontal lobe convexity with extensive perilesional edema. A tumor excision was done and histopathology studies revealed an angiomatous meningioma subtype. This case is reportable because angiomatous meningioma is a recognized rare entity. It is important to share this entity with other medical professionals and start to consider this condition in differential diagnosis when diagnosing a patient with an intracranial mass with an extensive peritumoral edema. Furthermore, the patient's unusual presentation of parkinsonian features and its occurrence with colorectal cancer history suggest a possible association between these conditions.

Preoperative prediction and histological stratification of intracranial solitary fibrous tumours by machine-learning models

AIM

To explore the effectiveness and feasibility of machine-learning models based on magnetic resonance imaging (MRI) radiomics features in differentiating intracranial solitary fibrous tumour (ISFT) from angiomatous meningioma (AM) and stratifying ISFT histologically.

MATERIALS AND METHODS

This study retrospectively recruited 268 patients with a histological diagnosis of ISFT (n=120) or AM (n=148), and 116 of the ISFT patients were used for stratified analysis of histological grade. The radiomics features were extracted from axial T1-weighted imaging (WI), T2WI and contrast-enhanced T1WI sequences. All patients were assigned randomly to the training group and test group in a ratio of 7:3. The models were optimised by 10-fold cross-validation in the training group, and the independent test group was used for further testing of the models. The performances of machine-learning models based on radiomics, clinical, and fusion features in predicting and stratifying ISFT were evaluated.

RESULTS

ISFT and AM differed significantly in terms of age, tumour shape, enhancement pattern, and margin. There was no significant difference in the clinical characteristics between World Health Organization (WHO) grade II and WHO grade III ISFT. When used to differentiate ISFT from AM, the area under the curve (AUC) values of the machine-learning models based on radiomics, clinical, and fusion features in the test group were 0.917, 0.923 and 0.950, respectively. When used for histological stratification of ISFT, the model based on the radiomics signature achieved an AUC value of 0.786 in the test group.

CONCLUSIONS

Machine-learning models can contribute in the prediction and histological stratification of ISFT non-invasively, which can help clinical differential diagnosis and treatment decisions.

Distinct clinical outcome of microcystic meningioma as a WHO grade 1 meningioma subtype

OBJECTIVE

To evaluate the clinicopathological characteristics, radiology, and long-term outcomes of microcystic meningiomas (MM) and compare it with other subtypes of meningiomas managed at a single neurosurgical center.

METHODS

A total of 87 consecutive patients who underwent surgical resection and were diagnosed as MM between 2005 and 2016 were enrolled for analysis. Clinicopathological, radiology, and prognostic information was collected and analyzed. Progression free survival (PFS) was compared with 659 patients with other subtypes of WHO grade 1 meningiomas and 167 patients with atypical meningiomas treated during the same period.

RESULTS

Fifty six females and 31 males with MM were analyzed. Peri-tumor brain edema was frequent on T2 WI (85%).12 patients (13.8%) experienced tumor progression during the mean follow-up of 101.66 ± 40.92 months. The median PFS was unavailable, and the 5, 10, and 15 year progression-free rates were 96.9%, 84.0%, and 73.9%, respectively. Univariate COX analysis demonstrated skull base location and higher Ki-67 index as significant negative prognostic factors for PFS (P < 0.05); multivariate analysis identified tumor location and Ki-67 index as independent factors (P < 0.01), as well. Of note, the PFS of MM was worse than other WHO grade 1 subtypes (P < 0.001), but better than atypical meningiomas (P < 0.001), and the PFS differences were retained even when the analysis was limited to the patients receiving GTR (P < 0.05).

CONCLUSION

The PFS of MM was worse than other WHO grade 1 subtypes and better than atypical meningiomas. Skull base location and higher Ki-67 index were independent negative prognostic factors in MM.

Preoperative Transarterial Embolization of a Large Petrotentorial Angiomatous Meningioma Using Combination of Liquid Embolic Materials: A Case Report

Intracranial angiomatous meningiomas are a rare WHO grade I histological variant of meningioma whose vascular component exceeds 50% of the total tumor area. Preoperative embolization of angiomatous meningiomas has rarely been reported previously. A 58-year-old woman was referred to our institute for a large petrotentorial hypervascular tumor presented with progressively worsening right facial paralysis and hearing loss for 6 months. Cranial computed tomography scan and magnetic resonance imaging revealed a large homogenously enhancing multilobulated mass involving middle and posterior cranial fossae with marked brainstem compression. The tumor extended into a right internal auditory canal and labyrinthine structures with destructive changes of bony structures. Magnetic resonance angiography showed hypervascularity in the tumor. Preoperative transarterial embolization using liquid embolic materials was successfully performed with resulting in almost complete devascularization of the tumor. Adequate hemostasis was achieved following gross total resection of the tumor (Simpson grade II). A histopathological examination confirmed the diagnosis of an angiomatous meningioma. Preoperative transarterial embolization of angiomatous meningioma with liquid embolic material was safe and effective in reducing perioperative blood loss and facilitating total tumor resection.

Role of diffusion-weighted imaging in differentiating angiomatous meningioma from atypical meningioma

BACKGROUND

Conventional magnetic resonance imaging (MRI) characteristics of angiomatous meningioma (AM) and atypical meningioma (ATM) sometimes overlap. However, there are significant differences in the treatment and prognosis of the two tumors. The aim of the study was to assess the role of diffusion-weighted imaging (DWI) in differentiating AM from ATM.

METHODS

Clinical, MRI, and pathological data of 25 patients with AM and 30 patients with ATM were retrospectively analyzed. Main clinical indexes, conventional MRI characteristics, and apparent diffusion coefficient (ADC) values were compared between the two groups, and receiver operating characteristic (ROC) curves were drawn to determine the diagnostic performance of ADC values in distinguishing AM from ATM.

RESULTS

The minimum ADC value (ADCmin), average ADC value (ADCmean), and relative ADC value (rADC) for AM (908.00 ± 117.00 × 10^-6 mm²/s, 921.04 ± 67.09 × 10^-6 mm²/s, and 1.15 ± 0.09, respectively) were significantly higher than those for ATM (710.50 ± 79.80 × 10^-6 mm²/s, 748.50 ± 67.27 × 10^-6 mm²/s, and 0.96 ± 0.09, respectively; all P < 0.05). ROC analysis showed that ADCmin had the best diagnostic performance in distinguishing AM from ATM, with an area under the curve value of 0.977. When using 759.00 × 10^-6 mm²/s as the optimal threshold, the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 90.00 %, 96.00 %, 92.72 %, 96.40 %, and 88.90 %, respectively.

CONCLUSIONS

DWI plays an important role in differentiating AM from ATM, and ADCmin is the most promising potential parameter that can improve the preoperative diagnostic accuracy of both tumors.

Calvarial angiomatous meningioma developed in the diploe

Background:

Angiomatous meningioma is a rare subtype of meningiomas. To the best of our knowledge, there have been no reports of intradiploic angiomatous meningioma.

Case Description:

A 53-year-old previously healthy woman was diagnosed with a calvarial lesion during a brain checkup. Cerebral magnetic resonance imaging showed an intradiploic tumor, 11 × 14 × 12 mm, in the right parietal bone. It was an enhancing, lobular tumor presenting as isointensity on T1- and hyperintensity on T2-weighted sequences, with an intense enhancement of the adjacent dura mater. Computed tomography revealed bone erosion at the tumor site, extending predominantly into the inner side, and sclerotic changes in the surrounding bone. Total resection was performed. Microscopically, the tumor tissue comprised cells with low-grade meningioma and intervening prominent vasculatures, consistent with angiomatous meningioma.

Conclusion:

Angiomatous meningioma should be considered as a differential diagnosis when an intradiploic tumor shows a lobular structure, intense enhancement of the adjacent dura mater, and sclerotic changes in the surrounding skull. These findings can support prompt tumor resection.

Non-Invasive Preoperative Imaging Differential Diagnosis of Intracranial Hemangiopericytoma and Angiomatous Meningioma: A Novel Developed and Validated Multiparametric MRI-Based Clini-Radiomic Model

BACKGROUND

Accurate preoperative differentiation of intracranial hemangiopericytoma and angiomatous meningioma can greatly assist operation plan making and prognosis prediction. In this study, a clini-radiomic model combining radiomic and clinical features was used to distinguish intracranial hemangiopericytoma and hemangioma meningioma preoperatively.

METHODS

A total of 147 patients with intracranial hemangiopericytoma and 73 patients with angiomatous meningioma from the Tiantan Hospital were retrospectively reviewed and randomly assigned to training and validation sets. Radiomic features were extracted from MR images, the elastic net and recursive feature elimination algorithms were applied to select radiomic features for constructing a fusion radiomic model. Subsequently, multivariable logistic regression analysis was used to construct a clinical model, then a clini-radiomic model incorporating the fusion radiomic model and clinical features was constructed for individual predictions. The calibration, discriminating capacity, and clinical usefulness were also evaluated.

RESULTS

Six significant radiomic features were selected to construct a fusion radiomic model that achieved an area under the curve (AUC) value of 0.900 and 0.900 in the training and validation sets, respectively. A clini-radiomic model that incorporated the radiomic model and clinical features was constructed and showed good discrimination and calibration, with an AUC of 0.920 in the training set and 0.910 in the validation set. The analysis of the decision curve showed that the fusion radiomic model and clini-radiomic model were clinically useful.

CONCLUSIONS

Our clini-radiomic model showed great performance and high sensitivity in the differential diagnosis of intracranial hemangiopericytoma and angiomatous meningioma, and could contribute to non-invasive development of individualized diagnosis and treatment for these patients.

Benign meningioma manifesting with acute subdural hematoma and cerebral edema: a case report and review of the literature

Background

Spontaneous subdural hematoma rarely presents with a hypervascular or malignant tumor but even less frequently in a benign tumor like meningioma. We encountered a patient with acute subdural hematoma associated with benign meningioma. Here, we report this case along with a review of previous reports, especially focusing on their clinical features and possible bleeding mechanisms.

Case presentation

A 53-year-old Asian woman presented with severe headache and progressive neurologic deterioration due to cerebral edema. The patient was submitted to open surgery for evacuation of the subdural hematoma and concurrent tumor removal on the ipsilateral parietal convexity. A hypervascular, encapsulated mass was identified during surgery and completely removed including the adjacent dura mater (Simpson grade 0). The tumor was histologically confirmed as an angiomatous meningioma (World Health Organization grade I). Her clinical course was uneventful after surgery.

Conclusions

Although meningiomas are commonly benign according to their histological traits, they can lead to spontaneous bleeding and cause neurologically unstable condition. Therefore, meningiomas need to be considered as a cause of spontaneous subdural hematoma if radiologically suspicious, which should be reflected by proper management for a positive outcome.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13256-021-02935-x.

Vascular endothelial growth factor concentrations in the cerebrospinal fluid of dogs with neoplastic or inflammatory central nervous system disorders

Background

Vascular endothelial growth factor (VEGF) is a key molecular driver of angiogenesis and vascular permeability and is expressed by a wide variety of neoplasms. Although blood VEGF concentrations have been quantified in intracranial tumors of dogs, cerebrospinal fluid (CSF) VEGF concentration might be a more sensitive biomarker of disease.

Objective

Concentrations of VEGF in CSF are higher in dogs with central nervous system (CNS) neoplasia compared to those with meningoencephalomyelitis and other neurologic disorders.

Animals

One hundred and twenty‐six client‐owned dogs presented to a veterinary teaching hospital.

Methods

Case‐control study. Cerebrospinal fluid was archived from dogs diagnosed with CNS neoplasia and meningoencephalomyelitis. Control dogs had other neurological disorders or diseases outside of the CNS. A commercially available kit was used to determine VEGF concentrations.

Results

Detectable CSF VEGF concentrations were present in 49/63 (77.8%) neoplastic samples, 22/24 (91.7%) inflammatory samples, and 8/39 (20.5%) control samples. The VEGF concentrations were significantly different between groups (P < .0001), and multiple comparison testing showed that both neoplastic and inflammatory groups had significantly higher concentrations than did controls (P < .05), but did not differ from each other. Gliomas and choroid plexus tumors had significantly higher VEGF concentrations than did the control group (P < .05).

Conclusions and Clinical Importance

Cerebrospinal fluid VEGF concentrations may serve as a marker of neoplastic and inflammatory CNS disorders relative to other conditions.

Intracranial Angiomatous Meningioma: A Clinicopathological Study of 23 Cases

Background

Intracranial angiomatous meningioma (AM) is a rare subtype of meningioma. Here, we investigated the clinical and pathological features of AMs.

Materials and Methods

We performed a retrospective study of 23 intracranial AMs verified by postoperative pathology at Huashan Hospital North between 2013 and 2018. Clinical data, radiological and pathological findings, and information on treatment and outcomes were collected and analyzed. Additionally, the literature on intracranial AMs was reviewed.

Results

The sample comprised 13 men and 10 women with AMs. The mean age was 54.2 years, and the mean duration of symptoms was 14.9 months. Headache and epilepsy were the most common symptoms. The most common AMs locations were the cerebral convexity and parasagittal/falx region. The rates of vascular signs, homogeneous enhancement, and peritumoral brain edema (PTBE) on magnetic resonance images were high. Histologically, besides typical meningioma cells, AMs had an abundant vascular component and low Ki-67 index. The extent of PTBE was related to microvessel density (MVD) of tumors, but not to the expression of MMP9 or VEGF. Simpson grade I resection was achieved in 15 cases, and grade II resection was achieved in 7 cases. Twenty-one cases were followed up, and they all had favorable outcomes without recurrence.

Conclusion

AM is a type of meningioma with a rich blood supply and distinct clinical and pathological features. It showed a slight male predominance and was common at the cerebral convexity or parasagittal/falx region. Histologically, it showed benign biological characteristics despite frequent and severe PTBE, and the extent of PTBE was related to MVD of tumors. Simpson I resection is the best treatment, and the prognosis is usually good after total tumor removal, while gamma knife is recommended for small residual tumor.

A clinico-pathological and neuro-radiological study of angiomatous meningioma: Aggressive look with benign behaviour

Angiomatous meningioma is a rare variant tumor classified as WHO grade 1 meningioma and accounts for about 2.1% of all meningioma. Their clinical presentation, surgical management, and prognosis are almost similar to the classical meningioma. Despite of benign nature and being comparatively small in size, they look aggressive on radiology images like massive peritumoral edema and intense contrast enhancement. Being a unique subtype of meningioma, the studies on angiomatous meningioma are very limited. In this cross sectional retrospective study, we described the clinical presentation, radiology, histopathological features and differential diagnosis of 30 cases of angiomatous meningioma from a single centre. The clinical parameters include demographic profile, symptoms and radiological findings including location, extent, pattern, histopathology with World Health Organization (WHO) grade-2016, extent of tumour excision, recurrence and surgical outcome. Incidence of angiomatous meningioma in our study was 2.46% with male predominance. The most common location in our study was convexity. 27 out of 30 had histopathology reports of angiomatous meningioma and 3 had lipoangiomatous meningioma. The high vascularity and disproportionate peri-tumoral edema makes it a surgical challenge for excision. The complications and surgical outcome were analysed. The radiological anticipation of tumour subtype, meticulous pre-operative planning and intraoperative precautions remains a key for success.

Occurrence of Fibrotic Tumor Vessels in Grade I Meningiomas Is Strongly Associated with Vessel Density, Expression of VEGF, PlGF, IGFBP-3 and Tumor Recurrence

Angiogenesis is a key feature during oncogenesis and remains a potential target of antiangiogenic therapy. While commonly described in high-grade lesions, vascularization and its correlation with prognosis in grade I meningiomas is largely unexplored. In the histological classification, not only the number but also the composition of blood vessels seems to be important. Therefore, tumor vessel density and fibrosis were correlated with clinical and imaging variables and prognosis in 295 patients with intracranial grade I meningioma. Expression of pro-angiogenic proteins within the meningiomas was investigated by proteome analyses and further validated by immunohistochemical staining. Fibrotic tumor vessels (FTV) were detected in 48% of all tumors and strongly correlated with vessel density, but not with the histopathological tumor subtype. Occurrence of FTV was correlated with a 2-fold increased risk of recurrence in both univariate and multivariate analyses. Explorative proteome analyses revealed upregulation of VEGF (vascular endothelial growth factor), PlGF (placental growth factor), and IGFBP-3 (insulin-like growth factor-binding protein-3) in tumors displaying FTV. Immunohistochemical analyses confirmed strong correlations between tumor vessel fibrosis and expression of VEGF, PlGF, and IGFBP-3. Presence of FTV was strongly associated with disruption of the arachnoid layer on preoperative MRI in univariate and multivariate analyses. In summary, the occurrence of fibrotic tumor vessels in grade I meningiomas is strongly associated with vessel density, disruption of the arachnoid layer, expression of VEGF, PlGF, IGFBP-3 and tumor recurrence.

High Tumor Mitochondrial DNA Content Correlates With an Improved Patient's Outcome in WHO Grade III Meningioma

Background: Studies have shown mitochondrial genome content (mtDNA content) varies in many malignancies. However, its distribution and prognostic values in high-grade meningioma remain largely unknown. In this retrospective study, we sought to assess a putative correlation between the mtDNA content and clinical characteristics. Methods: Mitochondrial DNA was extracted from 87 World Health Organization grade III meningioma samples using a qPCR method. The distribution of mtDNA content in WHO grade III meningioma and its correlations with clinical variables were assessed. Furthermore, we prognostic values were also determined. Results: Mean mtDNA content was 617.7 (range, 0.8-3000). There was no mtDNA distribution difference based on the histological subtypes (P = 0.07). Tumors with preoperative radiation were associated with lower mtDNA content (P = 0.041), whereas no correlations with other clinical variables were observed. A high mtDNA content was associated with significantly better PFS (P = 0.044) and OS (P = 0.019). However, in patients who received postoperative radiotherapy, low mtDNA content was associated with better PFS (P = 0.028), while no difference in OS was observed (P = 0.272). Low mtDNA content was also associated with better OS and PFS in subgroups of patients with ER negative status (PFS, P = 0.002; OS, P = 0.002). Conclusions: Consistent with other tumors, high mtDNA content was associated with better outcome in WHO grade III meningioma in our cohort. However, for patients who received post-operative radiation therapy, low mtDNA content was associated with better PFS. These findings suggest that mtDNA content may further be explored as a potential biomarker for high-grade meningioma patients and for those who received postoperative radiation therapy.

ADC values of benign and high grade meningiomas and associations with tumor cellularity and proliferation - A systematic review and meta-analysis

INTRODUCTION

The aim of the present systematic review and meta-analysis was to compare the reported ADC values in different meningiomas and to analyze associations between ADC and cell count and proliferation activity in this tumor entity.

METHOD

MEDLINE library and SCOPUS database were screened for papers investigating ADC values of meningiomas up November 2019. The first primary endpoint of the systematic review was the reported ADC mean value of the meningioma groups. The second primary endpoint was the correlation coefficient between ADC values and proliferation index Ki 67 and cellularity.

RESULTS

For the discrimination analysis between benign and high grade meningioma 17 studies were suitable. There were 766 grade I tumors and 289 high grade meningiomas. The calculated mean ADC value of the benign grade I tumors was 0.93 × 10^-3mm²/s [95%-Confidence interval 0.84;1.03] and the mean value of the high-grade tumors was 0.77 × 10^-3mm²/s [95%-Confidence interval 0.73-0.80]. The pooled correlation coefficient between ADC and the proliferation index Ki 67 was r = -0.36 [95% CI -0.43; -0.28]. The pooled correlation coefficient between ADC and cellularity was r = -0.43 [95% CI -0.61; - 0.26].

CONCLUSION

No validated ADC threshold can be recommended for distinguishing benign from high grade meningiomas. Only a moderate inverse correlation was identified between ADC values and tumor microstructure in meningiomas and, therefore, ADC might not accurately enough to predict proliferation potential and cellularity in this entity.

Microcystic Meningiomas: MRI-Pathologic Correlation

BACKGROUND AND PURPOSE

Microcystic meningiomas (MM) are a distinctive, rare subtype of Grade I meningiomas with limited radiological descriptions. We intend to identify unique imaging phenotypes and seek radiopathological correlations.

METHODS

Retrospective analysis of histopathologically proven MM was undertaken. Clinicodemographic profiles, imaging, and histopathological characteristics were recorded. Spearman rank correlations among radiological and pathological attributes were performed.

RESULTS

Twenty-eight cases were analyzed (mean age = 45.5 years; M:F = 1:1.54; mean volume = 50.1 mL; supratentorial n = 27). Most lesions were markedly T2 hyperintense (higher than peritumoral brain edema-a unique finding) (89.3%) and showed invariable diffusion restriction, severe peritumoral brain edema (edema index >2 in 64.3%), a "storiform" pattern on T2-weighted images (T2WI) (75%), reticular pattern on postcontrast T1 (78.6%)/diffusion-weighted images (DWI) (65.4%), hyperperfusion, T1 hypointensity (84.6%), and absence of blooming on susceptibility-weighted image (80.9%). Storiform/reticular morphology correlated with large cysts on histopathology (ρ = .56; P = .005753).  Lesion dimension positively correlated with reticular morphology on imaging (ρ = .59; P = .001173), higher flow voids (ρ = .65; P = .00027), and greater microcystic changes on histopathology (ρ = .51; P = .006778). Peritumoral brain edema was higher for lesions demonstrating greater angiomatous component (ρ = .46; P = .014451).

CONCLUSIONS

We have elucidated varied neuroimaging features and highlighted pathological substrates of crucial imaging findings of MM. MM ought to be considered as an imaging possibility in an extra-axial lesion with a marked hypodensity on noncontrast computed tomography, markedly T2-hyperintense/T1-hypointense signal, and a storiform/reticular pattern on T2W/GdT1w//DWI.

Value of Apparent Diffusion Coefficient (ADC) and Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) in Differentially Diagnosing Angiomatous Meningiomas and Solitary Fibrous Tumors/Hemangiopericytomas

Background

To determine if ADC and DCE-MRI can be used to differentiate angiomatous meningiomas (AMs) from solitary fibrous tumors/hemangiopericytomas (SFT/HPCs).

Material/Methods

We retrospectively reviewed records of 103 patients from 1 January 1 2014 to 1 November 2018. We enrolled 41 patients who had undergone a 3T MRI, with histologically confirmed AMs in 20 (48.80%) patients, and SFT/HPCs in 21 (51.20%) patients. The ADC and DCE-MRI features were derived and then compared by 2 independent-samples t tests and Wilcoxon rank sum test to obtain the ROC.

Results

AMs had significantly lower ADC values than did SFT/HPCs, but AMs had significantly higher MCER values than did SFT/HPCs. A threshold value of 1.03×10⁻³ mm²/s for ADC to predict AMs from SFT/HPCs was estimated (AUC=0.902, sensitivity=88.20%, specificity=83.30%). Optimal diagnostic performance (AUC=0.825, sensitivity=84.60%, specificity=81.80%) was obtained when setting MCER=226.7% as the threshold value.

Conclusions

The ADC values of AMs were lower than those of SFT/HPCs; the MCER of AMs were greater than those of SFT/HPCs, and ADC was more useful than MCER, and these parameters could help diagnosis.

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.