Case report and literature review.
A 29-year-old previously healthy male presented with three weeks of right lower extremity weakness, progressing to the right upper extremity. Neurological examination revealed right hemiparesis, right Babinski sign, and ataxic gait. Brain MRI showed large, patchy lesion in the left frontal lobe with mild enhancement, lesion in the right insula, well-demarcated lesions in bilateral basal ganglia/thalami with diffusion restriction, with additional smaller foci in the supratentorial white matter bilaterally. Spinal cord MRIs unremarkable. Initial HIV testing negative but repeat HIV testing positive and CD4 count was 58. Lumbar puncture showed protein of 49 mg without pleocytosis. CNS toxoplasmosis suspected. Empiric trimethoprim-sulfamethoxazole initiated for 6 weeks. He was re-admitted 3 days after for nausea and vomiting. CSF toxoplasma IgG, cytology, and flow cytometry negative, but CSF JCV PCR returned positive, concerning for HIV-associated PML. Antiretroviral therapy initiated. Patient deteriorated, with concern for immune reconstitution inflammatory syndrome; corticosteroids started. Repeat imaging showed progression of lesions in the cortex, white matter, and basal ganglia with necrosis and hemosiderin deposition. Differential diagnosis included CNS lymphoma and opportunistic infection. The basal ganglia involvement was atypical for PML, and lack of enhancement was atypical for lymphoma. Brain biopsy confirmed PML.