Acute hemorrhagic leukoencephalitis: MRI and neuropathology findings

Representative axial T2-weighted (A), noncontrast T1-weighted (B), postcontrast T1-weighted (C), and fast fluid-attenuated inversion recovery (FLAIR) (D-F) 1.5-T MRI scans three days after neurologic symptom onset. Images show bilateral confluent asymmetric lesions in the posterior frontal, posterior temporal, parietal, and occipital lobes, and splenium of the corpus callosum. Lesions extend from the periventricular region to the subcortical white matter and gray-white junction. Lesions are seen with comparable sensitivity on T2-weighted vs FLAIR images and are mildly hypointense on T1-weighted images without contrast enhancement. There was no evidence of brain herniation or infratentorial lesions (not shown). (G) This slide of deep white matter exhibits fine vacuolation (arrowheads) due to edema, neutrophilic infiltrate (arrows), and a cluster of extravasation of erythrocytes (upper left-middle of image, thick arrows), all typical of acute hemorrhagic leukoencephalitis. Myelin stains showed loss of myelin staining in the edematous areas (not shown). There was no evidence of active infection. Hematoxylin and eosin; original magnification ×400.