Radiology profile as a potential instrument to differentiate between posterior fossa ependymoma (PF-EPN) group A and B.

Abstract Introduction Posterior fossa ependymoma (PF-EPN) was categorized into PF-EPN-A and PF-EPN-B subgroups based on the DNA methylation profiling. PF-EPN-A was reported to have poorer prognosis compared to PF-EPN-B. In this study, we particularly evaluated preoperative imaging to distinguish PF-EPN-A from PF-EPN-B. Patient and Methods Sixteen cases of PF-EPN were treated in our institution from 1999 to 2018. The patients were divided into PF-EPN-A and PF-EPN-B group based on the H3K27me3 immunostaining positivity. We evaluated progression free survival (PFS), overall survival (OS), as well as preoperative MRI and CT scan images in both groups. Based on T1WI and Gd-T1WI MR images, the tumor contrast rate was determined from dividing the volume of gadolinium enhanced tumor by the overall tumor volume. Results Nine cases (4 males and 5 females) were grouped as PF-EPN-A, and 7 (4 males and 3 females) as PF-EPN-B. The median age of PF-EPN-A and B were 4 and 43 year old, respectively. In PF-EPN-A group, the PFS median value was 32.6 months, and the OS median was 96.9 months. In contrast, PFS in PF-EPN-B was not reached a median value (P Conclusions Contrast rate less than 50%, based on the MR images, was characteristic in PF-EPN-A group. Comparatively, cystic component and absence of calcification were more characteristic in the PF-EPN-B group.