Endoscopy-verified occult subependymal dissemination of glioblastoma and brain metastasis undetected by MRI: prognostic significance

Abstract

Although various prognostic indices exist for patients with malignant brain tumors, the prognostic significance of the subependymal spread of intracranial tumors is still a matter of debate. In this paper, we report the cases of two intraventricular lesions, a recurrent glioblastoma multiforme (GBM) and a brain metastasis, each successfully treated with a neuroendoscopic approach. Thanks to this minimally invasive approach, we achieved good therapeutic results: we obtained a histological diagnosis; we controlled intracranial hypertension by treating the associated hydrocephalus and, above all, compared with a microsurgical approach, we reduced the risks related to dissection and brain retraction. Moreover, in both cases, neuroendoscopy enabled us to identify an initial, precocious subependymal tumor spreading below the threshold of magnetic resonance imaging (MRI) detection. This finding, undetected in pre-operative MRI scans, was then evident during follow-up neuroimaging studies. In light of these data, a neuroendoscopic approach might play a leading role in better defining the prognosis and optimally tailored management protocols for GBM and brain metastasis.

Decreased survival in glioblastomas is specific to contact with the ventricular-subventricular zone, not subgranular zone or corpus callosum

“…For example, widespread dissemination of tumor cells through CSF or along the length of VSVZ has been hypothesized [19, 32, 33]. Indeed, we noted contrast enhancement of the ipsilateral ventricular ependymal surface in a subset VSVZ+ GBMs (Supplemental Figure S3b–d).…”

The Utility of Diffusion and Perfusion Magnetic Resonance Imaging in Target Delineation of High-Grade Gliomas

“…Some studies indicated that the clinician can capture subtle changes, such as integrity damage and diffusivity changes caused by peritumoral edema or tumor infiltration, in neuronal structures and fibers through multimodality MRI [ 29 – 33 ]. Other studies suggested that multimodality MRI can be used to distinguish high-grade gliomas from metastatic tumors [ 34 – 37 ]. Recent studies have shown that multimodality MRI is a valuable noninvasive tool in differentiating residual/recurrent gliomas from postirradiation cerebral lesion [ 38 , 39 ].…”

Modified Pure Endoscopic Approach to Pineal Region: Proof of Concept of Efficient and Inexpensive Surgical Model Based on Laboratory Dissections

“…In addition, the endoscope may allow a clearer distinction of the interface between the tumor and the surrounding eloquent structures. [6][7][8][9][10][11][12][13][14][15][16][17] In 2008 Gore et al reported the first application of a pure endoscopic supracerebellar infratentorial approach for dealing with a pineal cyst, a minimally invasive alternative to conventional microsurgical procedures that requires no exposure of the venous sinuses. 1,18,19 However, potential bleeding coming from bridging veins and/or highly vascularized lesions may be extremely hard to control with the endoscopic instrumentation.…”