Cryptococcoma of the cerebellum
This is a difficult case, with the cerebellar lesion having unusual and non-specific appearances. A metastasis was considered most likely, especially in the setting of a lung mass, although even then appearances are atypical. The absence of diffusion restriction made pyogenic infections most unlikely.
The patient went on to have a craniotomy. The lesion appeared filled with translucent white material.
Histology confirmed the left cerebellar lesion as a cryptococcoma.