Fig. 1

MRI and histologic findings of case 1 with ATXN1::NUTM2A fusion. A MRI: T2WI—axial and coronal; T1WI axial, post gadolinium images showed a large mixed solid and cystic mass expanding the left cerebral hemisphere, rightward midline shift, and marked flattening and displacement of the brainstem and cerebellum [Blue arrows outline the tumor mass; white arrows indicate large blood vessels]. B The tumor demonstrates prominent myxoid stromal changes with reticular arrangement of cells. C, D The tumor showed interfaced nodules and diffuse sheets of undifferentiated round to ovoid cells. E The tumor cells showed a relatively uniform cytomorphology at a higher magnification. F, G The tumor cells are positive for ETV4 (F) and vimentin (G) by immunohistochemistry. (B, C, D and E: hematoxylin and eosin [H&E], 100x, 200 × and 400 × final magnification; F and G: ETV4 and vimentin, 200 × final magnification)