Fig. 1

Imaging and Histopatological features of MB1. Axial CT (a) and axial conventional MR (b T2w, c FLAIR T2w, d T1w) images demonstrate a heterogeneous posterior fossa tumor in the left cerebellar hemisphere with mild surrounding edema (arrowheads) and significant mass effect on the fourth ventricle. The lesion shows a hypointense rim (white arrows) and a cystic component on its medial side (*). Apparent diffusion coefficient map (e) reveals restricted diffusion in solid tissue (black arrows). On the perfusion sequences (f) by arterial spin labeling, the tumor was depicted as a low perfusion area. (g) Neoplasm is composed of densely cells with round to oval shaped hyperchromatic nuclei with scanty cytoplasm. (h) Neoplastic cells are arranged in nodule surrounded by a reticular fiber network (Gomori stain)