There is an extradural mass in the right posterior fossa. The lesion is T2 hyperintense with multiple internal septations. It demonstrates diffusion restriction with no appreciable contrast enhancement. It causes moderate mass effect, displacing the right cerebellum. It effaces, but does not compress the right transverse and sigmoid sinuses. There is no surrounding oedema. The fourth ventricle is patent and there is no hydrocephalus. A 5mm high T2 / low T1 focus in the left post-central gyrus demonstrates susceptibility artefact consistent with calcification on phase and CT suggests an old granuloma or burnt out cysticercosis. There are no other foci of susceptibility artefact. Parenchymal signal is otherwise normal throughout.
Conclusion: Extradural cystic mass in the right posterior fossa is almost certainly a "white" epidermoid.