Brain magnetic resonance imaging (panels a and b) and light microscopy findings on brain specimens from autopsy (panels c and d). Panel a. Axial T2-weighted magnetic resonance image (MRI): multifocal T2 hyperintense subcortical lesions with u-fiber involvement and no mass effect. Panel b. T1-weighted MRI with Gadolinium: lesions are hypointense. The frontal lesion shows very little peripheral enhancement. Panel c. Brain section-hematoxylin-eosin × 400: white matter showing two clusters of blue, oval shaped microsporidia surrounded by macrophages. Panel d. Brain section-hematoxylin-eosin × 400: microsporidia with the characteristic extruded polar tube.