69-year-old male presented with rapidly progressive cognitive decline. Past medical history is significant for TIA 6 years ago. Patient had also undergone FNAC for mediastinal lymphadenopathy 4 years ago and it was negative for malignancy.
Patient had h/o decreased interest in day-to-day activities of life with decreased verbal output and change in behavior including decreased motivation, difficulty in following complex commands, using curse words from past 2 months. His condition progressive declined over 2 months so that no longer able to perform routine activities of daily living. Neurological examination was significant for non-fluent aphasia with decreased word output, palilalia, using curse words, impaired repetition and copying. At outside facility, CT Head done & started on steroids for a possibility of ADEM vs CNS Lymphoma. On admission to our facility, MRI Brain w wo contrast showed T2/FLAIR hyperintensities in B/L frontal lobes with non-enhancing mass lesion involving white matter including corpus callosum. MRI spectroscopy showed relative depression of N-acetyl aspartate (NAA) and elevation of choline with no significant lipid lactate., suggestive of PML vs CNS Lymphoma.
Differential diagnosis of PML, tumor, post/para infectious, neurodegeneration, autoimmune encephalitis.