Supratotal Resection of Periventricular Glioblastomas and Pathomorphological Rationale for Extensive Removal of Subventricular Zone

The aim of the research was to reveal the pathomorphological patterns of periventricular glioblastoma (PVG) dissemination and assess the rationale for extended surgical removal of subventricular zone (SVZ) as a step towards supratotal resection.A total of 54 patients (16 females and 38 males, mean age 48.9 ± 13.4 years, range 22–69) with PVG were prospectively included in the study. Standard preoperative evaluation included an MRI using 3D T1 with Gd-enhancement, T2, and T2-FLAIR series. The neuronavigation system was used to identify the SVZ and to remove of ventricular wall, additionally to image-guided total tumor resection. The pathomorphological assessment of PVG features with the description of the SVZ and changes in perifocal brain matter was performed by two pathologists.The median Karnofsky Performance Scale (KPS) score raised from 67.8 to 81.9 in the postoperative period. The overall median survival was 13.0 ± 2.7 months. The low postoperative KPS score (p = 0.05) and basal ganglia invasion (p = 0.008) significantly decreased survival rates.Microscopically, the typical multilayer structure of SVZ was disrupted. The invasive spread of tumor cells in thesubventricular space was identified. The ependymal layer had prominent dystrophic alterations of cells and destruction of intracellular connections. The hyperplastic reaction on neoplastic process was typical for adjacent ependyma.The pathomorphological identification of periventricular glioblastoma invasion in the subependymal space supports the supratotal tumor resection with removal of adjacent SVZ as a potential source for relapse.