Fig. 2

Showing MRI brain axial sequences FLAIR/T2/T1 and T1 with contrast at various stages. Day 1, new non-enhancing cerebellar hemisphere T2 hyperintensities (larger on the right). The new ill-defined extensive T2 hyperintensity in the right middle cerebellar peduncle extending into the right cerebellar white matter is felt concerning for PML. Day 16, no pathological enhancement identified. The previously noted new high signal in the right cerebellar peduncle extending into the right cerebellar hemisphere is slightly more extensive than on the prior scan but no enhancement. Day 48, progression of right cerebellar and brainstem high signal and enhancement. Progression of the presumed PML in the right middle cerebellar peduncle extending into the right cerebellar hemisphere and now extending to the right side of the pons. Day 86, area of abnormal T2 high signal within the right middle cerebellar peduncle extending into the pons and right cerebellum is again demonstrated. There is increased T2 signal at the periphery of the lesion within the right cerebellar hemisphere, and involvement of the pons is also significantly increased, now extending to involve the central pons. New area of T2 low signal within the medial left cerebellar hemisphere and in the left cerebellum adjacent to the inferior left cerebellar peduncle faint peripheral enhancement in the area of increased FLAIR signal in the right cerebellar hemisphere. Faint enhancement within the peripheral aspect of the right cerebellar lesion suggestive of PML-IRIS. MRI findings are consistent with progression of disease with progressive involvement of the pons and new involvement of the left cerebellar hemisphere. Day 125, significant progression of high signal abnormality in the posterior fossa as described, now extending to the left of the midline associated with extensive patchy enhancement. The appearances would now be more in keeping with PML-IRIS. (These MRI-images are acquired through 1.5 T Machine)