Abstract A 36-year-old woman with type 2 diabetes mellitus and obesity presented with progressive balance disturbance over several months. She had an unremarkable family history and was born to healthy, non-consanguineous parents. On examination, she was alert, oriented, and conversant. She had a normal fundoscopy. There were no gross sensory or pyramidal motor abnormalities. Evaluation of coordination with finger-to-nose and rapid alternating movements testing revealed marked left-side dysmetria and ataxia. A gadolinium-enhanced magnetic resonance imaging (MRI) study revealed multiple cystic lesions, most notably in the pons (3 cm, exerting mass effect on the brainstem) and cerebral white matter, and extensive white matter hyperintensity on T2-weighted images. Computed tomography (CT) revealed small calcifications scattered within the centrum semiovale and right thalamus. The lumbar puncture was normal. A stereotactic biopsy of right frontal white matter was performed and submitted to pathology.

1. The differential diagnosis for this lesion? 2. Additional investigations to confirm the diagnosis? 3. The diagnostic features (radiologic and pathologic) of this lesion?