PMC8088500_01
Imaging features of intraparenchymal subependymoma. (a) Axial gadolinium T1-weighted image showing a hypointense mass on the left occipital lobe, with mild contrast enhancement. (b) Axial T2 sequence showing a hyperintense heterogeneous mass. (c) Axial FLAIR sequence with hyperintense evident signal. (d) Axial diffusion-weighted sequence, with no diffusion restriction. (e) Axial ADC with increased signal compared to brain parenchyma. (f) Axial susceptibility weighted imaging showing small dots with hypointense signal within the lesion.
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F1
Careful analysis revealed the lesion was adjacent and related to the occipital and atrial portions of the left lateral ventricle [Figure 1].
Intraoperative images. (a) A 4 cm corticectomy was made and a soft, smooth-contoured, and lobulated mass was evident. (b) At the final steps of the resection it was possible to see the tumor corridor connected the walls of the ventricular system, choroid plexus (white asterisk) and the atrium of the left lateral ventricle (white arrow). (c) Ventricular drainage was placed under direct view for better managing the postoperative care. (d) Use of navigation to confirm the extent of the resection and confirming positioning of ventricular drainage.
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F2
After total removal, an external ventricular drainage was placed under direct view for better managing the postoperative care [Figure 2].
Imaging of postoperative MRI. (a) Day 1 after surgery axial gadolinium T1-weighted image showing no signs of contrast enhancement or presence of hypointense lesion previously visualized. (b) Day 1 after surgery axial T2 sequence without evidence of tumor. (c) Day 1 after surgery axial FLAIR sequence with slight hyperintense signal on tumor borders, compatible with recent postoperative imaging and no evidence of residual tumor. (d) One year after surgery axial gadolinium T1-weighted image showing no signs of contrast enhancement or tumor recurrence. (e) One year after surgery axial T2 sequence without evidence of tumor recurrence. (f) One year after surgery axial FLAIR sequence without evidence of tumor recurrence and improvement on hyperintense signal on tumor borders.
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F3
Postoperative MRI was performed on the 1st day after surgery and revealed a complete resection [Figure 3]. One year postoperative MRI was performed on long-term follow-up, and showed no signs of recurrence [Figure 3].
(a) Positivity for glial fibrillary acidic protein. (b) Negativity for epithelial membrane antigen. (c) Clusters of cellular proliferation embedded in dense fibrillar matrix and large acelular zones. (d) MIB-1 staining showing labeling index of 5%.
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F4
There was no evidence of active mitosis, necrosis, or vascular endothelial proliferation [Figure 4]. Ki67/MIB-1 labeling index were 5% on hot spots [Figure 4].