Microsurgical management of suprasellar and intraventricular meningiomas

Transpalpebral Approach for Microsurgical Removal of Tuberculum Sellae Meningiomas

Background:

The evolution of skull base approaches associated with individualization of surgical corridor and minimizing the collateral damage. Achieving the radical removal of tumor and preserving the neurological status of the patient is possible, both with the traditional approaches and keyhole approaches. Our work presents experience using the transpalpebral approach (TPA) for microsurgical removal of tuberculum sellae meningioma (TSM).

Materials and Methods:

A total of 15 patients with meningiomas underwent microsurgical removal of TSM through TPA. Ten patients were women and five were men. The standard preoperative diagnostic protocol includes magnetic resonance imaging with contrast enhancement, brain computed tomography for neuronavigation. We assess surgical complications, functional and cosmetic outcomes, and surgical parameters, including the time of surgery and intraoperative blood loss.

Results:

Visual impairment was finding in 100% patients, including slight decrease of vision (46,7%, seven patients), partial vision field loss (six patients, 40%), and serious visual impairment (two patients 13.3%). Visual improvement was noted in ten cases (66.7%), there was no improvement in four cases (26.7%), and one case (6.6%) had transient visual worsening for 4 days and slow improvement in 1 month. Headache disappeared in three patients (50%). There were no cases of cerebrospinal fluid leak. Transient frontal hypoesthesia was noted in all patients (100%) without permanent deficit. Transient palsy of the frontal muscle was noted in four patients for 4–6 months. Histological examination revealed WHO Grade I meningioma in 14 cases and in 1 case WHO Grade II meningioma. No deaths were identified in follow-up at 12 months. The average value of the Modified Rankin Scale was 1.4. The mean length of stay in hospital was 5.

Conclusion:

TPA is technically difficult and requires some experience to work in deep structures in a small surgical corridor. This technique can be good alternative to traditional fronto-lateral, supraorbital keyhole craniotomies, and endoscopic endonasal approaches.

Intraventricular meningiomas frequently harbor NF2 mutations but lack common genetic alterations in TRAF7, AKT1, SMO, KLF4, PIK3CA, and TERT

Intraventricular meningiomas (IVMs) account for less than 5% of all intracranial meningiomas; hence their molecular phenotype remains unknown. In this study, we were interested whether genetic alterations in IVMs differ from meningiomas in other locations and analyzed our institutional series with respect to clinical and molecular characteristics. A total of 25 patients with surgical removal of an IVM at our department between 1986 and 2018 were identified from our institutional database. Median progression-free survival (PFS) was 79 months (range of 2–319 months) and PFS at 5 years was 86%. Corresponding tumor tissue was available for 18 patients including one matching recurrence and was subjected to targeted panel sequencing of 130 selected genes frequently mutated in brain cancers by applying a custom hybrid capture approach on a NextSeq500 instrument. Loss of chromosome 22q and 1p occurred frequently in 89 and 44% of cases. Deleterious NF2 mutations were found in 44% of IVMs (n = 8/18). In non-NF2-mutated IVMs, previously reported genetic alterations including TRAF7, AKT1, SMO, KLF4, PIK3CA, and TERT were lacking, suggesting alternative genes in the pathogenesis of non-NF2 IVMs. In silico analysis revealed possible damaging mutations of APC, GABRA6, GSE1, KDR, and two SMO missense mutations differing from previously reported ones. Interestingly, all WHO°II IVMs (n = 3) harbored SMARCB1 and SMARCA4 mutations, indicating a role of the SWI/SNF chromatin remodeling complex in aggressive IVMs.

Natural history of intraventricular meningiomas: systematic review

Review the data published on the subject to create a more comprehensive natural history of intraventricular meningiomas (IVMs). A Medline search up to March 2018 using "intraventricular meningioma" returned 98 papers. As a first selection step, we adopted the following inclusion criteria: series and case reports about IVMs, as well as papers written in other languages, but abstracts written in English were evaluated. Six hundred eighty-one tumors were evaluated from 98 papers. The majority of the tumors were located in the lateral ventricles (602-88.4%), fourth ventricle (59-8.7%), and third ventricle (20-2.9%). These tumors accounted for a mortality rate of 4.0% (25 deaths) and a recurrence rate of 5.3% (26 recurrences). The majority of the tumors were grade I (89.8%) and consisted of the following subtypes: fibrous, 39.7% (n = 171); transitional, 22.0% (n = 95); meningothelial, 18.6% (n = 80); angiomatosus, 3.2% (n = 14); psammomatous, 2.6% (n = 11); and others, 13.9% (n = 60). Forty-five patients (7.4%) presented with grade II (GII) tumors, and 17 patients (2.8%) presented with grade III (GIII) tumors. These tumors follow the histopathological distribution of meningiomas in general, with the exception of the higher prevalence of the fibrous subtype, possibly due to its embryonic origin. Recurrence and mortality were lower than in other localizations likely due to a complete surgical resection rate than in the convexity and skull base, which suggests that GTR is the gold standard for the management of IVMs.