Chordoid meningioma: a clinico-pathological study of an uncommon variant of meningioma

Favorable Long-Term Outcomes of Chordoid Meningioma Compared With the Other WHO Grade 2 Meningioma Subtypes

BACKGROUND

WHO grade 2 meningiomas, including atypical, chordoid, and clear cell subtypes, form a heterogenous group of meningiomas with varying aggressiveness and clinical behavior.

OBJECTIVE

To demonstrate the differences of clinical-histopathological characteristics and long-term outcomes among these 3 subtypes.

METHODS

A total of 609 consecutive patients diagnosed with WHO grade 2 meningiomas (543 atypical meningiomas [AMs], 36 chordoid meningiomas [CMs], and 30 clear cell meningiomas [CCMs]) from 2010 to 2018 were enrolled in this study. We compared the clinical-histopathological characteristics and long-term outcomes in these 3 subtypes and assessed survival differences among the subtypes. Targeted panel sequencing of meningioma-relevant genes was performed in the cases of CM.

RESULTS

The patients with CCM were significantly younger than those with AM ( P < .001) and CM ( P = .016). CMs were more likely to receive gross total resection than AMs and CCMs ( P = .033). The Ki-67 index was lower ( P < .001) while the progesterone receptors-positive rate was higher ( P = .034) in CM than in AM and CCM. Importantly, survival analysis demonstrated that CM had better progression-free survival ( P = .022) and overall survival ( P = .0056) than non-CM tumors. However, the PFS of CM was still worse than WHO grade 1 meningiomas ( P < .001). Alterations in NF2 (20.6%) and KMT2C (26.5%) were associated with poorer PFS in CM ( P = .013 for NF2 ; P = .021 for KMT2C ).

CONCLUSION

Patients with CM had better long-term postoperative outcomes than the other WHO grade 2 subtypes. A lower Ki-67 index, higher PR status, higher extent of resection, and lower frequency of NF2 alteration might contribute to favorable clinical outcomes of CM.

Clinical features, radiological findings, and prognostic factors for primary intracranial chordoid meningioma

OBJECTIVES

Chordoid meningioma (CM) is an infrequent histologic subtype of meningiomas. Owing to its low occurrence, this subtype has been rarely described. Our subject was to explore the clinical features, radiological characteristics, and prognostic factors of primary intracranial chordoid meningioma.

METHODS

We reviewed the medical records and collected follow-up information of 34 cases who had been surgically treated and histologically diagnosed with CM at the Department of Neurosurgery, West-China Hospital of Sichuan University, from January 2009 to December 2021.

RESULTS

Among all 7,950 meningioma cases, the proportion of primary intracranial CM was 0.43% (34/7,950). The median diagnosis age was 47 (ranging from 12 to 74) and the gender ratio (male to female) was 2.1:1. For radiological features, heterogeneous enhancement, skull base, and ventricular localization, cystic degeneration and dural tail sign were common in CM cases. In treatment, gross total resection (GTR) was achieved in 22/34 cases (64.7%) and subtotal resection (STR) was achieved in 12/34 cases (35.3%). Further, 11/34 patients (32.4%) had received postoperative adjuvant radiotherapy (RT). The follow-up duration ranged from 4 to 157 months after operation. The progression rate was 20.7% (6/29) and the median of PFS was 38 months. By survival analysis, accepting adjuvant radiotherapy and achieving GTR were correlated with longer progression-free survival for prognosis.

CONCLUSION

CM is a rare subtype of meningiomas. In our series, it mainly involved adults and did not show a predilection for women compared with meningiomas in general. For a better prognosis, gross total resection and postoperative adjuvant radiotherapy are recommended. Nevertheless, due to the restriction of the series sample, patients lost for follow-up and inherent biases of a retrospective study, more cases and a shorter follow-up duration are needed for better management of chordoid meningioma.

Epigenetic and genomic profiling of chordoid meningioma: implications for clinical management

Chordoid meningioma is a morphological variant of meningioma designated as WHO grade 2. However, the recurrence rates varied widely in different case series, and to date, a unifying molecular genetic signature has not been identified. Among 1897 meningiomas resected at our institution, we identified 12 primary chordoid meningiomas from 12 patients. Histologically, all 12 cases had predominant (> 50%) chordoid morphology. Ten were otherwise grade 1, and two were also atypical. We performed DNA global methylation profile, copy number variation analysis, and targeted next-generation sequencing on 11 chordoid meningiomas, and compared to those of 51 non-chordoid, mostly high grade meningiomas. The chordoid meningiomas demonstrated a unique methylation profile in tSNE, UMAP, and hierarchical heatmap clustering analyses of the most differentially methylated CpGs. The most common copy number variation in chordoid meningioma was loss of 1p (7/11, 64%). Three chordoid meningiomas had 2p loss, which was significantly higher than the non-chordoid control cohort (27% vs 7.2%, p = 0.035). 22q loss was only seen in the two cases with additional atypical histological features. Chordoid meningiomas were enriched in mutations in chromatin remodeling genes EP400 (8/11,73%) KMT2C (4/11, 36%) and KMT2D (4/11, 36%), and showed low or absent NF2, TERT, SMO, and AKT1 mutations. Prognosis wise, only one case recurred. This case had atypical histology and high-grade molecular features including truncating NF2 mutation, 1p, 8p, 10, 14, 22q loss, and homozygous deletion of CDKN2A/B. Progression free survival of chordoid, otherwise grade 1 meningioma was comparable to non-chordoid WHO grade 1 meningioma (p = 0.75), and significantly better than chordoid WHO grade 2 meningioma (p = 0.019). Conclusion: the chordoid histology alone may not justify a universal WHO grade 2 designation. Screening for additional atypical histological or molecular genetic features is recommended.

Utility of multiparametric pre-operative magnetic resonance imaging in differentiation of chordoid meningioma from the other histopathological subtypes of meningioma-a retrospective study

PURPOSE

To determine the magnetic resonance imaging (MRI) features which could pre-operatively differentiate chordoid meningioma (CM) from other histopathological subtypes of meningioma.

METHODS

Retrospective analysis of pre-operative MRI of cases with histopathologically confirmed diagnosis of meningioma during the last 5 years at our institute was done. T1W, T2W, FLAIR sequences, and post-contrast enhancement were evaluated on a qualitative scale. Normalized ADC ratios (nADCR) and normalized fractional anisotropy ratios (nFAR) were derived. The intratumoral susceptibility score (ITSS), presence of sunburst pattern of vasculature, bone changes, tumour-parenchyma interface, and oedema-to-tumour ratio were also determined.

RESULTS

A total of 81 lesions were analyzed out of which 15 were CM. CM showed a higher relative contrast enhancement as compared to all other subtypes except for angiomatous and microcystic meningioma. Relative signal intensity on FLAIR could differentiate CM from transitional meningioma. nFAR was found to be significantly higher in fibroblastic meningioma and significantly lower in microcystic meningiomas as compared to CM. Anaplastic meningiomas were remarkable for bone changes and an ill-defined tumour-brain interface in significantly higher proportion of cases as compared to CM. nADCR > 1.5 was found to be an independent predictor of CM with a sensitivity of 84.6%, specificity of 89.8%, positive predictive value of 64.7%, and negative predictive value of 96.4%.

CONCLUSION

Routine pre-operative MRI may be able to differentiate CM from other meningioma subtypes and a cut-off value of greater than 1.5 for nADCR could be predictive of > 50% chordoid histology of meningioma with a high sensitivity, specificity, and negative predictive value.

Meningioma: A Pathology Perspective

Meningiomas are dural-based neoplasms that account for ∼37% of all intracranial tumors in the adult population. They can occur anywhere within the central nervous system and have a predilection for females. The World Health Organization classifies meningiomas into 3 grades based on increased risk of recurrence and associated mortality in grade III tumors. Although most tumors are categorized as low-grade, up to ∼15%-20% demonstrate more aggressive behavior. With the long-recognized association with neurofibromatosis type 2 gene mutation, putative driver mutations can be attributed to ∼80% of tumors. Several germline mutations have also been identified in some cases of familial meningiomatosis such as SMARCE1, SUFU, PTEN, and BAP1. Finally, in addition to genetic data, epigenetic alterations, specifically deoxyribonucleic acid methylation, are being increasingly recognized for their prognostic value, potentially adding objectivity to a currently subjective grading scheme.

A Case of Tuberculum Sellae Chordoid Meningioma Treated via Extended Endoscopic Endonasal Trans-sphenoidal Surgery

A 68-year-old female was admitted to our hospital with right-sided hemianopsia. Magnetic resonance imaging (MRI) demonstrated a well-enhanced tuberculum sellae region tumor. The patient underwent surgical tumor resection via an extended endoscopic endonasal trans-sphenoidal approach and the tumor was totally removed. The mass was extremely soft and there was no clear attachment between it and the dura mater. Furthermore, the histopathological findings obtained for the tumor during intra-operative rapid diagnosis were divergent from typical meningioma. We therefore diagnosed the tumor intra-operatively as a pituitary adenoma. However, the post-operative pathological diagnosis for the tumor was chordoid meningioma (CM). CM is a rare subtype of meningioma, and most of such tumors arise in the convexity. In the preoperative MRI in the present case, meningioma was suspected; however, since we did not consider CM for differential diagnosis, we failed to reach an accurate diagnosis during the operation. Tuberculum sellae CM is very rare, and only a few cases have been reported previously. The surgical strategy will differ greatly depending on whether the tumor is a meningioma or a pituitary adenoma, especially when treatment involves the dura mater. The pre and/or intra-operative diagnosis is thus very important for developing an accurate treatment strategy. We report here the details of our rare case and describe the intra-operative features of tuberculum sellae CM.