PMC6069373_01
Preoperative and postoperative MRI of RELA-fusion positive ependymoma. Preoperative axial (a) T1-weighted gadolinium-enhanced, (b) T2-weighted, (c) FLAIR, and (d) coronal T1-weighted contrast-enhanced imaging demonstrate a ring-enhancing lesion with cystic central component and perilesional edema in the left frontal cortex. Postoperative (e) T1-weighted contrast-enhanced and (f) T1-weighted nonenhanced imaging show a gross total resection. Functional MRI data for (g) reading, (h) word recognition, and (i) lip movement are shown. Compared with the tumor, language cortex localizes posterolateral while motor cortex is further posterior
SNI-9-144-g001.jpg
PMC6069373_01_SNI-9-144-g001.jpg
F1
Diagnostic T1-weighted imaging with contrast revealed a heterogeneously enhancing lesion in the left frontal lobe with significant mass effect and surrounding vasogenic edema, initially concerning for an astrocytoma or oligodendroglioma [Figure 1].
Preoperative and intraoperative MR perfusion of RELA-fusion positive ependymoma. Preoperative (a) T1-weighted with contrast, (b) CBF, (c) CBV, and (d) mean transit time (MTT) imaging demonstrates increased diffusion in the ring-enhancing portion of the tumor, suggestive of an aggressive lesion (arrow). This perilesional area (arrow) correlated with the solid tumor component seen on pathological analysis [Figure 3a-c]. A central hypoperfusive tumor mass (arrowhead in a-d) correlated with the more papillary component of the tumor [Figure 3d-f]. Intraoperative (e) T1-weighted contrast-enhanced imaging suggested a gross total resection. However, intraoperative (f) CBF, (g) CBV, and (h) MTT demonstrated posterior perilesional hyperperfusion that was suggestive of residual tumor, a conclusion that was later confirmed
SNI-9-144-g002.jpg
PMC6069373_01_SNI-9-144-g002.jpg
F2
Conventional intraoperative studies (T1 with and without contrast, T2, FLAIR, DWI/ADC, stereotactic T1) demonstrated gross total resection [Figure 2]; however, a 1-cm2 hyperperfused area of tissue in the posterior aspect of the resection margin was identified.
Pathological analysis of RELA-fusion positive ependymoma. (a, d) The hematoxylin and eosin-stained tissue showed two morphologic patterns to the tumor. Some areas of the tumor consist of solid sheets of tumor cells (a-c), whereas other areas of the tumor have papillary architecture (d and f). The tumor nuclei are round and regular with evenly distributed chromatin. Areas with increased cellularity, predominately in the solid areas of the tumor, show up to six mitotic figures in ten high-power fields. Small foci of tumor necrosis (not pictured) are also identified. A prominent vascular network is present in the tumor with fibrotic vessels. The tumor cells cuff the vessels, although there is a lack of an acellular zone containing fibrillary projections. (b and e) The immunohistochemical stain for GFAP shows patchy positivity in the tumor cells, with the tumor cells surrounding the vessels being notably positive. (c and f) The MIB-1/Ki-67 stain is positive in approximately 60% of the tumor nuclei in the solid areas of the tumor (c), and occasional nuclei are positive in the papillary areas (f). The MIB-1/Ki-67 index overall is greater than 10% in the tumor. The immunohistochemical stain for IDH-1 is negative (not pictured). All photomicrographs taken at 100x total magnification
SNI-9-144-g003.jpg
PMC6069373_01_SNI-9-144-g003.jpg
F3
The final pathological results of the original tumor and biopsy of lateral, posterior, and deep resection cavity margins were consistent with RELA-fusion positive anaplastic ependymoma [Figure 3].