Presentation
Cognitive decline in a known HIV-positive patient on antiretroviral therapy.
Patient Data
There is supratentorial atrophy, inappropriate for age. There is a somewhat symmetric, ill-defined, low-density periventricular deep white matter. Non-contrast CT brain is otherwise normal.
MRI confirmation of confluent, somewhat symmetric, non-enhancing, periventricular and deep white matter abnormal T2 and T2 FLAIR high signal intensity. There is also external capsular, posterior limb of the internal capsule (PLIC) and cerebellar deep white matter involvement. There is no mass effect and no midline shift.
Case Discussion
In a patient with HIV, the features are consistent with HIV encephalopathy. In this instance, subcortical, U-fiber and cerebellar involvement is noted. A differential diagnosis of progressive multifocal leukoencephalopathy (PML) is difficult to exclude based on the above imaging features.
The lumbar puncture was relatively normal. John Cunningham's (JC) viral antibody studies for both CSF and serum were negative. A brain biopsy can assist in confirming/ excluding PML. MR spectroscopy can also be considered for further interpretation.