Advanced neuroimaging findings of pseudotumoral hemicerebellitis in an elderly male requiring surgical decompression.

Acute cerebellitis is an inflammatory process that usually affects bilateral cerebellar hemispheres in the pediatric population. Pseudotumoral hemicerebellitis is an extremely rare presentation in which unilateral cerebellar involvement mimics a tumor that can exert significant mass effect on the surrounding structures, which may require surgical intervention. Magnetic resonance imaging characteristics that suggest cerebellitis include cerebellar swelling, T2 hyperintensity, and pial enhancement. Advanced neuroimaging, including MR perfusion and MR spectroscopy, may be helpful in excluding other diagnoses. The authors present the case of pseudotumoral hemicerebellitis in the oldest documented patient, a 73-year-old man who required surgical decompression, and they provide a brief discussion of advanced neuroimaging findings.