Intracranial clear cell meningioma: a clinicopathologic study of 15 cases

Research Progress of Artificial Intelligence in the Grading and Classification of Meningiomas

A meningioma is a common primary central nervous system tumor. The histological features of meningiomas vary significantly depending on the grade and subtype, leading to differences in treatment and prognosis. Therefore, early diagnosis, grading, and typing of meningiomas are crucial for developing comprehensive and individualized diagnosis and treatment plans. The advancement of artificial intelligence (AI) in medical imaging, particularly radiomics and deep learning (DL), has contributed to the increasing research on meningioma grading and classification. These techniques are fast and accurate, involve fully automated learning, are non-invasive and objective, enable the efficient and non-invasive prediction of meningioma grades and classifications, and provide valuable assistance in clinical treatment and prognosis. This article provides a summary and analysis of the research progress in radiomics and DL for meningioma grading and classification. It also highlights the existing research findings, limitations, and suggestions for future improvement, aiming to facilitate the future application of AI in the diagnosis and treatment of meningioma.

Adjuvant Stereotactic Radiosurgery for Clear Cell Meningiomas

OBJECTIVE

Clear cell meningiomas (CCM) are an uncommon meningioma subtype marked by aggressive growth and high rates of recurrence despite initial resection. The present study evaluates the adjuvant benefit of stereotactic radiosurgery (SRS) for residual or recurrent tumors.

METHODS

After review of our prospectively maintained database, we identified 6 patients (3 female) with histologically confirmed Grade 2 CCMs. The median age of the patients at the time of SRS was 45 years. Five patients had undergone prior gross total surgical resection and 1 patient had subtotal resection before SRS. The median SRS treatment volume was 4.7 cc and the median radiosurgical margin dose was 13 Gy (range: 10-15 Gy).

RESULTS

The median follow-up time was 35.5 months (range 6-168 months). Three patients achieved tumor control after the first SRS procedure. Three patients experienced tumor progression at 4, 22, and 32 months after initial SRS. Tumor control was obtained in 2 of these patients after additional SRS. One patient with multiple SRS procedures had suspected adverse radiation effect that was successfully treated with corticosteroids followed by bevacizumab.

CONCLUSIONS

Tumor control was maintained in 5 of 6 patients after one or more SRS procedures. SRS should be considered for early intervention after surgical resection of CCM. To maximize the tumor control rate, patients with diagnosed CCM should be treated more generously and higher margin dose should be prescribed. Patients with CCM should be counselled that more than one SRS may be necessary to provide sustained tumor control.

Central nervous system clear cell meningioma: a systematic literature review

Clear cell meningiomas are a rare histological subtype of World Health Organization (WHO) grade II meningioma. Despite its relatively low frequency, clear cell meningioma has attracted considerable attention because of its unique pathological characteristics, clinical behavior, and challenging management considerations. The purpose of our systematic review is to provide clinicians with a better understanding of this rare disease. PubMed was searched for articles in the English language published from 1988 to 2023 June. The keywords were as follows: "clear cell meningioma," "clear cell" and "meningioma." We analyzed clinical manifestations, radiological manifestations, pathological features, comprehensive treatment strategies, and prognosis to determine the factors influencing recurrence-free survival (RFS). Recurrence-free survival curves of related factors were calculated by the Kaplan‒Meier method. The log-rank test and Cox univariate analysis were adopted to assess the intergroup differences and seek significant factors influencing prognosis and recurrence. Fifty-seven papers met the eligibility criteria, including 207 cases of clear cell meningioma (CCM), which were confirmed by postoperative pathology. The fifty-seven articles involved 84 (40.6%) males and 123 (59.4%) females. The average age at diagnosis was 27.9 years (range, 14 months to 84 years). Among the symptoms observed, headache, neurologic deficit, and hearing loss were the most commonly reported clinical manifestations. Most tumors (47.8%) were located in the skull base region. Most tumors showed significant enhancement, and homogeneous enhancement was more common. A total of 152 (74.1%) patients underwent gross total resection (GTR), and 53 (25.9%) patients underwent subtotal resection (STR). During the follow-up, the tumor recurred in 80 (39.4%) patients. The log-rank test and the Cox univariate analysis revealed that tumor resection range (GTR vs. STR) and adjuvant treatment (YES vs. NO) were significant predictors of recurrence-free survival (RFS). Clear cell meningioma is a rare type of meningioma with challenging diagnosis and therapy. The prognosis of this disease is different from that of regular meningiomas. Recurrence remains a possibility even after total tumor resection. We found that the surgical resection range and adjuvant treatment affected the recurrence period. This finding provides significant guidance for the treatment of clear cell meningioma.

Pituitary Adenoma Coexistent with Sellar Clear Cell Meningioma Unattached to the Dura: Case Report and Treatment Considerations

Collision tumors involving the sella are rare. Intrasellar collision tumors are most commonly composed of a combination of pituitary adenomas and pituitary neuroendocrine tumors; however, collision tumors consisting of a pituitary adenoma and intrasellar meningioma are exceedingly rare. The authors present the case of a 47-year-old man who presented with progressive right eye vision loss. Magnetic resonance imaging showed a large, heterogeneously enhancing sellar mass with suprasellar extension. Using a transcranial approach with a right subfrontal craniotomy, near-total resection of the mass was achieved. Histologic analysis confirmed a diagnosis of a gonadotroph adenoma with concomitant clear cell meningioma (CCM). This patient was discharged with improvement in visual acuity and no signs of diabetes insipidus. Given the indistinguishable radiographic characteristics of pituitary adenoma and CCM, a preoperative diagnosis of a collision tumor was difficult. This case was uniquely challenging since the CCM component lacked the classic dural attachment that is associated with meningiomas on neuroimaging. CCMs are classified as central nervous system (CNS) World Health Organization (WHO) grade 2 tumors and tend to behave more aggressively, therefore warranting close surveillance for signs of tumor recurrence. This is the first case to report a collision tumor consisting of pituitary adenoma and CCM.

Histogram analysis of tensor-valued diffusion MRI in meningiomas: Relation to consistency, histological grade and type

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Tensor-valued dMRI facilitates prediction of meningioma consistency, grade and type.

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Tensor-valued dMRI corroborates findings of diffusion tensor and kurtosis imaging.

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MK and MK_A is associated with firm and MD with variable meningioma consistency.

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Variability of MK_I in the vicinity of the tumor is associated with meningioma grade.

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MK_{A 50} and MK_{I 50} separates psammomatous meningiomas from other meningioma types.

Background

Preoperative radiological assessment of meningioma characteristics is of value for pre- and post-operative patient management, counselling, and surgical approach.

Purpose

To investigate whether tensor-valued diffusion MRI can add to the preoperative prediction of meningioma consistency, grade and type.

Materials and methods

30 patients with intracranial meningiomas (22 WHO grade I, 8 WHO grade II) underwent MRI prior to surgery. Diffusion MRI was performed with linear and spherical b-tensors with b-values up to 2000 s/mm². The data were used to estimate mean diffusivity (MD), fractional anisotropy (FA), mean kurtosis (MK) and its components—the anisotropic and isotropic kurtoses (MK_A and MK_I). Meningioma consistency was estimated for 16 patients during resection based on ultrasonic aspiration intensity, ease of resection with instrumentation or suction. Grade and type were determined by histopathological analysis. The relation between consistency, grade and type and dMRI parameters was analyzed inside the tumor (“whole-tumor”) and within brain tissue in the immediate periphery outside the tumor (“rim”) by histogram analysis.

Results

Lower 10th percentiles of MK and MK_A in the whole-tumor were associated with firm consistency compared with pooled soft and variable consistency (n = 7 vs 9; U test, p = 0.02 for MK_{A 10} and p = 0.04 for MK₁₀) and lower 10th percentile of MD with variable against soft and firm (n = 5 vs 11; U test, p = 0.02). Higher standard deviation of MK_I in the rim was associated with lower grade (n = 22 vs 8; U test, p = 0.04) and in the MK_I maps we observed elevated rim-like structure that could be associated with grade. Higher median MK_A and lower median MK_I distinguished psammomatous type from other pooled meningioma types (n = 5 vs 25; U test; p = 0.03 for MK_{A 50} and p = 0.03 and p = 0.04 for MK_{I 50}).

Conclusion

Parameters from tensor-valued dMRI can facilitate prediction of consistency, grade and type.

Paediatric supra- and infratentorial multiple giant clear cell meningioma: A report of a rare case and review of the literature

Clear cell meningiomas (CCMs) account for only approximately 0.2% of all meningiomas and are classified as grade II tumours by the World Health Organisation. Most of the previously described intracranial CCMs are single tumour entities. Multiple intracranial CCMs are extremely rare, and due to their low incidence, information on multiple CCM remains limited; hence, researchers and practitioners also have a limited understanding of its aetiology, clinical manifestations, and treatment options. Herein, we report a case of sporadic multiple intracranial CCM in a child that presented with a 3-month history of gait instability and mild dysphagia. Brain magnetic resonance imaging showed one lesion in the right frontoparietal lobe and another giant lesion on the ventral side of the brainstem, extending to the middle fossa. The lesions were completely resected in two stages. Postoperative histopathological examination confirmed CCM. The patient was followed up for 2 years without recurrence. To the best of our knowledge this is the first reported case of paediatric sporadic multiple intracranial CCM. In addition, we reviewed the relevant literature to discuss the pathogenesis, imaging findings, and treatment methods of this rare disease.

Clinical Manifestation, Management and Prognosis of Clear Cell Meningioma: An Evidence-Based Review

Clear cell meningioma (CCM) is an uncommon histologic subtype of meningioma classified as a WHO grade II tumor and accounting for less than 1% of all meningiomas. Demographically, younger patients are commonly affected without any remarkable gender preference. Moreover, CCM shows a unique anatomical site of involvement. It tends to occur in the cranium than the spine, whereas the basilar skull, posterior fossa, and lumbar spine have been the most frequently affected area. Although most cases present as typical the mass effect by the tumor, CCM exhibits characteristic imaging and histologic patterns. Even though surgical resection is the treatment of choice, recurrence-free survival is the biggest challenge and has been attempting to improve by adjuvant therapy. There is still debate about its management, outcome, and factors defining it. Herein, we aimed to summarize natural history, radiographic characteristics, histological features, treatment strategies to guide the best possible individualized care for the most favorable outcome.

Clear cell histology portends a worse prognosis than other WHO grade II histologies

PURPOSE

Clear cell meningioma (CCM) is a rare WHO grade II meningioma variant, characterized by aggressive features and a high tumor recurrence rate. In this study, we compared overall and progression-free survivals between CCMs and other WHO grade II meningiomas.

METHODS

A retrospective institutional database review was performed to identify all patients who underwent surgical resection of a WHO grade II meningioma between 1997 and 2019. Overall survival and progression-free survival were compared between patients with clear cell meningiomas and patients with other WHO grade II meningiomas. Multivariable Cox proportional-hazards analysis was used to identify independent predictors of tumor recurrence and survival.

RESULTS

We included a total of 214 patients in this study (43 CCMs, 171 other WHO grade II meningiomas). Patients with CCMs had significantly shorter progression-free (p = 0.001) and overall (p = 0.026) survivals than patients with other grade II meningiomas. In multivariable analysis, clear cell histology was a significant and powerful independent predictor of tumor recurrence (HR 1.93; 95% CI 1.14-3.26) when controlling for tumor location, extent of resection, and adjuvant radiation. In multivariable analysis, clear cell histology correlated with increased mortality (HR 1.96, 95% CI 0.97-3.94), though this was not statistically significant.

CONCLUSION

This is the first study to compare overall and progression-free survivals between CCMs and other WHO grade II meningiomas. Clear cell histology predicts a higher risk of tumor recurrence and mortality than other grade II histologies. Future studies may help to understand the impact of these findings and the treatment implications.

Clear Cell Meningioma: A Clinicopathologic Study of a Rare Meningioma Subtype in 35 Patients

OBJECTIVE

Clear cell meningioma (CCM) is a rare histologic variant, accounting for only 0.2%-0.8% of all meningiomas. Given their relative infrequency, few cases have been reported. We have presented one of the largest series of patients with intracranial CCM and reported the treatments and outcomes of these patients.

METHODS

Patients with histologically proven CCM from 2003 to 2018 were identified for inclusion in the present study. Relevant clinical and radiographic data were obtained via retrospective review and analyzed. Kaplan-Meier and Cox proportional hazards analyses were used to compare overall and progression-free survival.

RESULTS

A total of 35 patients had undergone surgical resection for CCM, including 18 women and 17 men, with a mean age of 59.3 years. Gross total resection was achieved in 22 patients (62.9%), and 11 patients (31.4%) had received adjuvant postoperative radiotherapy. Tumors recurred in 17 patients (48.6%), with a mean time to recurrence of 31.3 months. The mean postoperative follow-up was 66.3 months. On multivariable analysis, adjuvant radiotherapy and gross total tumor resection were both independently associated with prolonged progression-free survival (P < 0.033), although not with overall survival (P >0.274).

CONCLUSIONS

The data from the present series of 35 patients with CCM have shown distinct contrasts to previous series, with an older mean age and a nearly 1:1 male/female ratio. Although gross total resection and adjuvant postoperative radiotherapy were both independently associated with longer progression-free survival for patients with CCM, tumor recurrence has remained a challenge in the treatment of these patients.

An Aggressive Extension of Dumbbell-Type Pediatric Skull Base Meningioma: A Case Report with Review of the Literature

BACKGROUND

Pediatric meningiomas account for less than 2% of pediatric brain tumors. Pediatric clear cell meningiomas (CCMs) occurring in the posterior fossa are particularly rare. Therapeutic strategies differ among the previous pediatric CCM case reports. Therefore, to clarify the clinical features of pediatric CCMs, we report a rare case of dumbbell-type pediatric CCM and a corresponding literature review.

CASE DESCRIPTION

A 7-year-old boy with complaints of headache, left facial palsy, dysarthria, and left-sided ataxic gait was emergently admitted to our hospital. His consciousness level was slight stupor, with Glasgow Coma Scale score 3-5-6, and he showed left ptosis, dysarthria, and ataxias of the left trunk and extremities. Magnetic resonance imaging (MRI) scan showed acute obstructive hydrocephalus because of the tumor's compression of the brainstem. The dumbbell-shaped tumor extended from the lateral wall of the cavernous sinus, through the left Meckel's cave, to the cerebellopontine angle. Physical examination and perioperative MRI scan showed no evidence regarding neurofibromatosis type I or II. The tumor was removed in a 2-staged operation. Postoperative proton therapy was done to treat some residual tumors. One year after postoperative proton therapy, there is no recurrence, and apart from left corneal and facial hypesthesia, he is healthy.

CONCLUSIONS

We reported a rare case of pediatric skull base-type CCM with huge extension originating from the anteromedial wall of Meckel's cave firmly adhered to the cavernous sinus wall to the posterior fossa that was successfully treated with surgery and postoperative proton therapy. CCM has a high recurrence rate; therefore, careful prolonged follow-up is needed.

Advances in Diagnostic Immunohistochemistry for Primary Tumors of the Central Nervous System

As genomic characterization becomes increasingly necessary for accurate diagnosis of tumors of the central nervous system, identification of rapidly assessible biomarkers is equally important to avoid excessive cost and delay in initiation of therapy. This article reviews novel immunohistochemical markers that may be used to determine mutation status, activation of signaling pathways, druggable targets, and cell lineage in many diverse tumor types. In particular, recently added entities to the 2016 WHO classification of central nervous system tumors will be addressed, including IDH-mutant gliomas, diffuse midline glioma, epithelioid glioblastoma, angiocentric glioma, RELA-rearranged ependymoma, embryonal tumors (medulloblastoma, atypical teratoid/rhabdoid tumor, pineoblastoma, embryonal tumor with multilayered rosettes, and other genetically defined high-grade neuroepithelial tumors), and meningiomas associated with germline alterations.

Pediatric clear cell meningioma involving the middle cranial fossa in the context of NF2 and SMARCE1 mutations

Meningiomas are an uncommon entity in children and adolescents. <30 cases of pediatric clear cell meningioma (CCM), a World Health Organization (WHO) Grade II tumor, have been reported in the literature. These tumors are more likely to recur than the more common WHO Grade I meningiomas, especially with incomplete surgical resection. CCMs are most commonly found in the spine and posterior cranial fossa. Recently, SMARCE1 mutations have been linked to the development of CCM. To evaluate the progression of pediatric CCM in the context of emerging genetic knowledge, we reviewed all 45 cases of CCM at our institution for a 23 year period (1997-2019) to identify pediatric cases. Forty-four of the tumors arose in adults from age 34-81 years. The one pediatric case originally presented at age 4 years; the patient was found to have a CCM in the left cavernous sinus projecting into the posterior fossa, associated with a novel germline SMARCE1 mutation and somatic NF1 and DMD mutations. After two years, the patient had a recurrence of the tumor and underwent a second resection. This is the 5th reported case of CCM in the middle cranial fossa, and the only recurrent case, as well as the only reported case of recurrent pediatric CCM associated with a germline SMARCE1 mutation. Further study of the natural history of tumors associated with germline SMARCE1 loss could potentially inform prognosis.

Differentiation Researches on the Meningioma Subtypes by Radiomics from Contrast-Enhanced Magnetic Resonance Imaging: A Preliminary Study

BACKGROUND

Meningioma subtypes are one of the most common key points to the treatment and prognosis of patients. The purpose of this study was to investigate the differential diagnostic value of radiomics features on meningioma.

METHODS

A total of 241 patients with meningioma who had undergone tumor resection were randomly selected including 80 with meningothelial meningioma, 80 with fibrous meningioma, and 81 with transitional meningioma. These meningiomas were divided into 4 groups including: meningothelial versus fibrous (group 1), fibrous versus transitional (group 2), meningothelial versus transitional (group 3), and meningothelial versus fibrous versus transitional (group 4). All patients were examined using the same magnetic resonance scanner (GE 3.0 T) and the preoperative contrast-enhanced T1-weighted images were available. Radiomics features from the contrast-enhanced T1-weighted images of 241 patients were evaluated by 2 experienced radiology specialists.

RESULTS

A total of 385 radiomics features were extracted from the images of each patient. Several preprocessing methods were applied on the radiomics dataset to reduce the redundancy and highlight differences between different meningioma before the Fisher discrimination analysis was adopted and leave one out cross validation methods were used for the model validation. The differentiation accuracies of the Fisher discriminant analysis model for groups 1, 2, 3, and 4 were 99.4%, 98.8%, 100% and 100%, respectively; leave one out cross validation method was achieved for group 1, 2, 3, and 4 with the accuracies of 91.3%, 95.0%, 100%, and 94.2%, respectively.

CONCLUSIONS

Radiomics features and the combined Fisher discriminant analysis could provide satisfactory performance in the preoperative differential diagnosis of meningioma subtypes and enable the potential ability for clinical application.

Hereditary clear cell meningiomas in a single family: three-cases report

Clear cell meningiomas (CCMs) are rare subtypes of meningiomas and usually treated by maximum safely achievable tumor resection. We here present three hereditary cases with CCMs which were confirmed by Sanger sequencing of lymphocyte DNA. Gross total resection was achieved in a 5-year-old son with a spinal CCM and a 34-year-old father with a CCM in the cerebellopontine angle (CPA). For a 14-year-old daughter with CCM in the CPA, total resection was not achieved due to its large size. Early detection by screening high-risk family with CCM is strongly recommended.

Clinical Features, Treatment, and Prognostic Factors of 56 Intracranial and Intraspinal Clear Cell Meningiomas

OBJECTIVE

Intracranial and intraspinal clear cell meningiomas (CCMs) are rarely reported because of their extremely low incidence, and the current understanding of CCM is poor. The purpose of this study was to analyze the incidence and the clinical, radiologic, pathologic, and prognostic features of intracranial and intraspinal CCMs.

METHODS

Among 14,310 cases of intracranial and intraspinal meningiomas that were surgically treated between 2006 and 2016 at Beijing Tian Tan Hospital, 56 were chosen for analysis and retrospectively reviewed. To determine which parameters were associated with longer progression-free survival (PFS) and overall survival (OS), statistical analysis was performed.

RESULTS

CCMs accounted for approximately 0.39% of all intracranial and intraspinal meningiomas. Patients with CCM had a mean age of 32.3 years and there was a female predilection (20 males and 36 females). Gross total resection was achieved in 35 cases, and subtotal resection was achieved in 21 cases. All patients were followed up for 10-206 months after surgery. Twenty-six patients experienced tumor recurrence, and the median PFS was 48.0 months. The 1-year, 3-year, and 5-year PFS was 87.5%, 59.8%, and 41.8%, respectively. Twelve patients died of tumor recurrence, and the median OS was not available. The 1-year, 3-year, and 5-year OS was 98.2%, 91.3%, and 65.8%, respectively. Univariate analysis showed that total tumor removal was significantly associated with a better prognosis. Multivariate analysis confirmed only Simpson grade III and IV resection as an independent risk factor for shorter PFS. Radiotherapy mildly improved PFS after both gross total resection and subtotal resection, showing no significant difference because of the small sample size and short follow-up duration.

CONCLUSIONS

CCM is a rare subtype of World Health Organization grade II meningioma. CCM typically involves young patients and shows a female predilection and high recurrence rate. When possible, total resection is the primary and most suitable treatment for CCM. For patients with primary tumors, radiotherapy is recommended after the initial operation regardless of the extent of resection. For patients with disease recurrence, secondary surgery combined with radiotherapy might serve as an effective treatment.

Surgical Management and Outcome Experience of 53 Cerebellopontine Angle Meningiomas

Background Meningiomas follow schwannomas as the second most common cerebellopontine angle (CPA) tumors. We investigate the diagnosis, management, and prognosis of this disease. Methods We reviewed the cases with the CPA meningiomas in our institution in Shaanxi, China from January 2012 to December 2015. Charts were retrospectively examined and patients were divided into two groups: 1) surgical treatment with a retrosigmoid approach for tumor resection and 2) stereotactic radiosurgery treatment only. Patients were followed up and outpatient records were also reviewed. Results Forty-nine patients underwent surgical resection via the retrosigmoid approach, while the other four underwent Gamma Knife® stereotactic radiosurgery (Elekta AB, Stockholm, Sweden) only. The most common presenting symptoms included hearing loss/tinnitus, vertigo, and headache; only 8.2% were asymptomatic. The largest diameter and base of each tumor varied from 4.0 to 5.5 cm and 3.0 to 5.0 cm, respectively. The tumors extended into different directions, mainly towards the tentorium and internal acoustic meatus (IAM). Eighty-three percent of surgical patients had a gross total resection. One death occurred due to pulmonary inflammation. Tumor recurrence was noted in 6.1% of patients. Postoperative trigeminal disturbance, facial nerve palsy, and hearing deterioration or loss were the most common immediate and delayed postoperative complications; most patients partially or completely recovered after hospital discharge. Intraoperative neuro-electrophysiological monitoring, complete resection, and postoperative radiation were key factors for reducing complications and recurrence. Conclusions The retrosigmoid approach offers an ideal visual field for exposing and resecting CPA meningiomas in a large series of cases. In our experience, it is one of the most useful and commonly used surgical approaches for removing meningiomas of this region.

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.

Pediatric intracranial clear cell meningioma: a clinicopathological study of seven cases and literature review

BACKGROUND

In this study, we reported seven cases of pediatric intracranial clear cell meningiomas (CCMs) in our institution and reviewed the relevant literature to investigate the clinicopathological characteristics, treatment options, and prognosis of these rare tumors.

METHODS

From January 2005 to June 2016, we retrospectively reviewed seven pediatric intracranial CCMs in terms of their clinical data, preoperative MRI features, and prognosis. Moreover, a critical review of the English language literature was also conducted.

RESULTS

The patients consisted of two males and five females with a median age of 10.5 years (range 6-15 years) at initial surgery. Petroclival and cerebellopontine angle area was the most common location site (5/7). Accordingly, the most common initial manifestation was hearing loss (3/7), and the mean interval from onset of symptoms to admission was 6.8 months (1.5-24 months). Gross total resection was achieved in five patients. Of the six tumors with immunohistochemical records, MIB-1 labeling index varied from 3 to 20 % (mean 8.1 %). During the follow-up period (mean 76.9 months, range 16-180 months), four patients had experienced tumor recurrences and three patients died due to recurrences.

CONCLUSIONS

Pediatric intracranial CCMs have a tendency to recur. There is a significant relationship between MIB-1 labeling index and recurrence. Gross total resection is recommended; if not available, adjuvant radiotherapy should be used to reduce the recurrent rate. In addition, postoperative MRI follow-up should be monitored at an interval time after resection.

Clinical features of clear cell meningioma: a retrospective study of 36 cases among 10,529 patients in a single institution

BACKGROUND

Clear cell meningioma (CCM) is a rare subtype of meningioma. We present the largest series of 36 CCMs and evaluate several prognostic factors of patient's clinical outcome.

METHODS

Thirty-six patients with pathologically confirmed CCM among a total of 10,529 meningioma patients were retrospectively reviewed.

RESULTS

CCM constituted 0.3 % of the intracranial meningiomas and 1.4 % of the intraspinal meningiomas. The male-to-female ratio (36 vs 64 %) for CCMs was similar to that for total meningiomas (28 vs 72 %) patients (chi-squared test, p = 0.3). The mean age at diagnosis of CCM patients (29.3 ± 18.4 years) was significantly younger than that of total meningiomas (49.8 ± 11.9 years) patients (t-test, p = 0). During the follow-up, 15 patients (42 %) suffered from tumor recurrence. The recurrence time ranged from 10 months to 12 years, with a median time of 29 months. Kaplan-Meier survival analysis showed that patients after total resection (Simpson grades I and II) had significantly longer progression-free survival (PFS) time than those after subtotal resection (Simpson grades III and IV) (log-rank test, p = 0.006). However, age (≤20 years or >20 years, p = 0.9), gender (p = 0.3), postoperative radiotherapy (p = 0.4), progesterone receptor staining (positivity or negativity, p = 0.2), and Ki-67 index (≤5 % or >5 %, p = 0.4) did not have significant effects on patients' PFS time.

CONCLUSIONS

The proportion of CCM in spinal meningiomas is likely to be much larger than that in intracranial meningiomas. CCMs should be resected totally when possible to decrease the risk of recurrence or prolong patient's PFS time.

A five year-old child with clear cell petro-clival meningioma: case report with clinical and histopathological long-term follow-up

BACKGROUND

Only a few cases have been previously published about clear cell meningiomas in children, the majority of them in the location of the spine. We describe an unusual case of clear cell meningioma occurring at the petro-clival region in a 5-year-old child. We further seek to determine the impact of several growth factors as well as the AKT1 mutation on the tumor growth pattern.

CASE PRESENTATION

A five-year-old girl was presented with a one-week history of cephalgia, ataxia, and left sided torticollis. Magnetic resonance imaging (MRI) revealed a dumbbell-shaped homogeneously petro-clival gadolinium-enhancing mass. A staged operative approach was chosen, and a complete removal of the tumor was achieved. Due to recurrent tumor progression, the child underwent several tumor surgeries and two cranial radiations. None of the treatments were able to stop tumor progression. Consequently, the child died at the age of 14 after further extensive intracranial and extracranial tumor progression. The initial histological examination revealed a clear cell meningioma WHO grade II with an MIB-1 labeling index of <1%, which gradually increased with every recurrence up to 10% by the last progression at the age of 13 years. Analogically, an increasing overexpression of epidermal growth factor receptor (EGFR), the platelet-derived growth factor receptor (PDGFR), and the vascular endothelial growth factor receptor (VEGFR) was observed with each recurrence. The AKT1 (E17K) mutation in the tumor was not detectable in all investigated specimens.

CONCLUSION

Pediatric clear cell meningiomas WHO grade II are very rare. Our data demonstrate the progressive overexpression of EGF-, PDGF-, and VEGF-receptors in each recurrence, providing one of these receptors as targeted therapy in such cases. Further evaluation of these growth factors in clear cell meningioma is required to establish the optimal treatment of these aggressive tumors.

Pediatric intracranial clear cell meningioma associated with a germline mutation of SMARCE1: a novel case

PURPOSE

Intracranial clear cell meningioma (CCM) represents a rare and potentially more aggressive subgroup of meningioma that is observed more frequently in children and adolescents. Despite its characterization as a histological entity, there is little evidence identifying tumorigenic etiologies. Recently, a novel mutation in SMARCE1, encoding a subunit of the SWI/SNF chromatin remodeling complex, was identified in a cohort of spinal CCMs. To date, no intracranial CCM has been subjected to analysis.

METHODS

We report the case of an isolated intracranial CCM in a 14-year-old girl. Gross total resection was achieved following a two-stage approach with no evidence of tumor recurrence 8 months following presentation.

RESULTS

Exon sequencing identified a germline mutation in SMARCE1, which was also present in tumor DNA. Extensive literature review confirmed our study is the first to seek and report a genetic anomaly for childhood intracranial CCMs outside of the NF2 gene locus, and the first to make an association between a germline SMARCE1 mutation and childhood intracranial CCMs.

CONCLUSIONS

Together with the previous description of SMARCE1 mutations in spinal CCMs, our report suggests that SMARCE1 aberrations may be implicated in establishing a clear cell histology irrespective of meningioma location. We would advocate that, where feasible, genetic sequencing is performed on future new cases of childhood neuraxial CCMs and includes interrogation of the SMARCE1 gene.

Intracranial Papillary Meningioma

BACKGROUND:

Papillary meningioma (PM) is an uncommon meningioma subtype, and the clinical characteristics remain unclear.

OBJECTIVE:

To determine the clinical characteristics and prognosis of PM.

METHODS:

The clinical data of 30 PM patients were collected, the samples were reexamined, and the patients' prognoses were based on clinical observations and calculated according to the Kaplan-Meier method.

RESULTS:

The 30 patients included 16 males and 14 females (median: 34.0 years upon initial diagnosis). Of the 48 intracranial operations in the 30 patients, total removal was attained in 34 surgeries, and subtotal removal in 14 surgeries. Radiotherapy was provided in 20 patients. In 40 specimens with follow-up, 29 attained the positive aggressive factors. Six tumors showed positive progestogen receptor (PR) combined with negative Bcl-2. The median follow-up period was 39.0 months. Tumor recurrence occurred in 18 patients (median: 17.0 months); the recurrence rates following total removal and subtotal removal were 57.1% and 100%, respectively. Fourteen patients died of the recurrence. In the univariate analyses, positive aggressive factors (P = .021), positive PR combined with negative Bcl-2 immunoreactivity (P = .011), the extent of resection (P = .001), and radiotherapy (P = .002) were significantly related to progression-free survival. The MIB-1 labeling index was not significantly related to progression-free survival (P = .88).

CONCLUSION:

PM is a rare subtype of meningioma with a tendency of recurrence. The extent of resection is an important prognosis factor. The presence of positive histopathological index increases the recurrence risk. Positive PR combined with negative Bcl-2 immunoreaction might predict a good prognosis. Postoperative radiotherapy may play a vital role in prolonging the time to tumor recurrence.

Intracranial clear cell meningioma in two children with blood relations: two case reports and literature review

Intracranial clear cell meningioma (CCM) is very rare and often has an aggressive clinical course. The predilection site of intracranial CCM in children was cerebellopontine angle where represents challenging tumor resection because of the vicinity of brainstem, vertebral artery, and lower cranial nerve. Therefore, special consideration is required for this tumor.We report two cases with intracranial CCM in a family and reviewed the literature concerning pediatric intracranial CCM. Case 1 is a 4-year-old boy with a tumor at the right posterior fossa. Case 2 is an 8-year-old boy with a left basilar region tumor. Gross total resection and subtotal resection was achieved in case 1 and case 2, respectively. Case 1 had no tumor recurrence at 12 months after the operation. Case 2 received cyber-knife radiosurgery (CKS) after subtotal resection at 4 months, and the residual tumor had gradually shrunk. Comprehensive chromosomal number aberrations in both patients were revealed by array-comparative genomic hybridization, and loss of neurofibromatosis 2 (NF2) gene was the common genetic abnormality in the two patients.To the best of our knowledge, this is the first report concerned two patients with CCM in a family, and the findings in this article suggest that CKS is a safe and effective adjuvant therapy for residual CCM after operation and NF2 gene mutation plays a role in tumorigenesis of pediatric intracranial CCM.