Objective:

To distinguish the imaging findings of HIV encephalopathy and PML in a patient recently diagnosed with AIDS and EBV-associated lymphoma treated with immunosuppressive chemotherapy, and the rationale for Pembrolizumab treatment.

Background:

PML is caused by reactivation of the JC virus in an immunocompromised patient. While commonly associated with HIV/AIDS, it can also occur in patients who receive immunosuppressive chemotherapy. Recent studies suggest a role for checkpoint inhibitors in treating PML, though the understanding of the risks/benefits in different clinical contexts is evolving.

Design/Methods:

Case report and literature review.

Results:

A 59-year-old man with AIDS and EBV-associated lymphoma, in remission after EPOCH-Rituxan and methotrexate, presented in status epilepticus after two-months of worsening cognition and language difficulties. Admission CD4 was 146, improved from a nadir <35 after starting Biktarvy 3-months prior. EEG showed a left temporal-parietal focus, in proximity to prior lymphoma involvement, but also abnormalities in the contralateral hemisphere. Seizures were controlled with three medications. Multiple LPs were unrevealing, including cytopathology and infectious studies. Lymphoma remained in remission. MRI demonstrated progression of bilateral, hazy, diffuse periventricular T2-hyperintensities first noted on MRI two-months prior, consistent with HIV-encephalopathy. Additionally, there were multiple, new, smaller, more densely hyperintense juxtacortical lesions involving U-fibers, concerning for PML. One juxtacortical lesion near the EEG seizure focus demonstrated a small area of enhancement. Initial CSF JC Virus PCR was negative, not surprising given the small total burden of PML-appearing lesions. JCV serum antibody was positive. Given the low CD4 and recent immunosuppressive chemotherapy, he was treated with pembrolizumab, in hopes of quickly improving T-cell function while the extent of potentially irreversible neurological injury from PML was still modest.  

Conclusions:

This case highlights the importance of recognizing and distinguishing the MRI findings, clinical presentation, and risk factors for PML. Early administration of pembrolizumab may improve PML outcomes.