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case_images: MRI Brain with and without contrast; axial T2 FLAIR (March 23, 2022). Subcortical T2 hyperintense signal abnormality involving the left brachium pontis/left cerebellar hemisphere with possible minimal right cerebellar involvement.
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case_images: At our hospital, the MRI of the brain revealed T2 hyperintense signal abnormalities in both subcortical cerebellar hemispheres, more pronounced on the left (Fig. 1).
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case_images: MRI Brain with and without contrast; axial T2 FLAIR (April 7, 2022). Stable geographical signal abnormalities of the posterior fossa compatible with the clinical diagnosis of PML. Stable additional nonspecific multifocal, overall mild signal changes of the supratentorial white matter.
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case_images: However, he returned the following month with a worsening gait disturbance, and new symptoms including dysarthria, dysmetria and left-sided nystagmus, despite a more than 3-log drop in his HIV RNA after 3 weeks of HAART (Table 1, Fig. 2).
case_images: MRI Brain with and without contrast; axial T2 FLAIR (May 28th, 2022). Significant interval worsening of signal abnormalities in the posterior fossa with now diffuse involvement of the pons, extension to the mesencephalon and markedly more pronounced involvement of the medulla, right middle cerebellar peduncle, and central cerebellum. Patchy areas of restricted diffusion are without a clear vascular territorial distribution. IRIS is less likely in the absence of contrast enhancement, but it cannot be completely excluded in the appropriate scenario.
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case_images: He was re-hospitalized and treated with pembrolizumab (2 mg/kg, single dose) but continued to worsen neurologically and a new MRI showed disease progression in the posterior fossa (Fig. 3).