Progressive Multifocal Leukoencephalopathy Presenting as Primary CNS Malignancy in an Immunocompetent Patient

Abstract

Progressive multifocal leukoencephalopathy (PML) is an infection caused by the John Cunningham virus (JCV), usually in an immunocompromised host. We present the case of a 74-year-old male who presented with a six-week history of progressive memory loss, episodic confusion, and aphasia. Cranial nerve, motor, sensory, and coordination testing were unremarkable. Magnetic resonance imaging (MRI) of the brain and spectroscopy were concerning for primary CNS lymphoma vs. diffuse glioma. Microscopic examination after the patient underwent left frontal stereotactic brain biopsy was suggestive of a viral infection, and further testing with JCV DNA in-situ hybridization (ISH) confirmed the diagnosis of PML. The patient's condition started resolving without treatment. This case demonstrates, to our knowledge, the first known case of primary PML masquerading as CNS lymphoma in modern literature.

Keywords: cns lymphoma; immunocompetent; jc virus; malignancy; pml; progressive multifocal leukoencephalopathy.

Figure 1. Key images from MRI brain with and without contrast, perfusion imaging, and MR spectroscopy

(a) T2 flair post-contrast showing diffuse abnormal left-hemispheric signaling (yellow arrows). (b) T2 flair post-contrast showing progression of diffuse abnormal left-hemispheric signaling (yellow arrows). (c) MRI perfusion showing elevated cerebral blood volume at the multilobar left hemispheric area of involvement (yellow circle). (d) MR spectroscopy showing a decrease in N-acetyl aspartate (yellow arrow).

Figure 2. Key images from MRI brain with and without contrast and perfusion imaging

(a) T2 flair post-contrast showing improvement of abnormal left-hemispheric signaling (yellow arrows). (b) T2 flair post-contrast showing abnormal left-hemispheric signaling, improved from initial study (yellow arrows). (c) MRI perfusion showing decreased cerebral blood volume compared to patient's initial study (yellow circle). (d) MRI perfusion showing persistence of decreased cerebral blood volume compared to prior study (yellow circle).