Western variant of brain intravascular lymphoma displaying three distinct evolutive radiologic stages.

Intravascular lymphoma is a rare type of extranodal diffuse large B-cell lymphoma characterized by proliferation of clonal lymphocytes within small- and medium-sized blood vessels and a relative sparing of surrounding tissues. It commonly affects the central nervous system (CNS), but its atypical presentation often leads to a delayed diagnosis. We report a unique case of a 53-year-old man presenting with confusion and ataxic gait. The initial magnetic resonance imaging (MRI) of the brain showed multifocal plaque-like CNS lesions suggestive of multiple sclerosis. His condition worsened rapidly, accompanied by persistent low-grade fever and further alteration in mental status. Follow-up MRI studies suggested new parenchymal brain lesions consistent with multiple evolving embolic strokes and subsequently with brain infarcts. Biopsy showed intravascular lymphomatous brain involvement. His condition continued to deteriorate, resulting in multiorgan failure and demise. To the best of our knowledge, these clear-cut MRI stages of brain intravascular lymphoma have not been previously reported in the scientific literature. Our findings are important as the diagnosis intravascular lymphoma is commonly made postmortem, given its rapidly progressive course and lack of typical symptomatology.