NI-53 * PROGRESSIVE MULTIFOCAL LEUKOENCEPHALOPATHY MIMICKING HIGH GRADE GLIOMA IN AN IMMUNOCOMPETENT PATIENT: A CASE REPORT

Abstract

Progressive multifocal leukoencephalopathy is an uncommon and fatal demyelinating disease of the central nervous system that is due to reactivation of the JC virus. It is most often seen in immunocompromised patients, such as those with HIV/AIDS or those on chronic immunosuppressive therapy. We present a case of biopsy-proven idiopathic PML in a presumed immunocompetent patient, with imaging characteristics suggestive of glioma. A 66-year-old white male with a history of cirrhosis presented with subacute onset of progressive deterioration of mental status, aphasia, and right hemiparesis. Laboratory and cerebrospinal fluid studies were unremarkable for any infection, autoimmune disease, and malignancy. MRI brain revealed a non-contrast enhancing lesion involving the left frontal, parietal, and temporal lobes with marked sparing of overlying cortex, characterized by increased T2/FLAIR hyperintensity, T1 hypointensity, and facilitated diffusion. MR spectroscopy of the lesion demonstrated elevated choline, with lactate peaks and decreased NAA. A high grade glioma was suspected and patient underwent a brain biopsy. Histological analysis revealed enlarged oligodendrocytes with myelin loss consistent with active demyelination. The enlarged oligodendrocytes had smudged nuclear chromatin, were positive for JC virus by in situ hydridization, and also showed strong staining for p53. A diagnosis of progressive multifocal leukoencephalopathy (PML) was made. Although rare in immunocompetent individuals, this unusual presentation suggests that PML be considered in the approach to the diagnosis and management of such lesions.