In the context of those imaging findings and the probably histological diagnosis, which further MRI study should be considered?
As CSF seeding is common at presentation, imaging with contrast of the whole neuraxis is recommended to identify drop metastases and leptomeningeal spread.
Left cerebellar hemisphere mass, very heterogeneous with cystic areas and only minimal enhancement of the solid component, has strikingly low ADC values (measured at 450 x 10-6 mm2/s) consistent with a highly cellular tumour. Medulloblastoma is by far the most likely diagnosis.