PMC7214636_01
(A) A summary of the disease course. (B) Axial sections of the brain MRI showed tumefactive lesions. (C) Improvement of the edema around tumefactive lesions. (D) The spine MRI demonstrated a lesion extending from the thoracic cord to conus.
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F1
Despite a good initial recovery, 10 months later the patient was admitted with confusion, slurred speech, left sided facial weakness, and ataxia (Figure 1A). A brain MRI showed contrast enhancing tumefactive lesions in the left peri-insular area, both corona radiatae and brainstem (Figures 1B,C). A brain MRI revealed a new enhancing lesion in the occipital horn adjacent to the left lateral ventricle and a spine MRI showed a contrast enhancing lesion in the thoracic cord extending to the conus (Figure 1D).
Brain biopsy neuropathology. (A) Biopsy appeared hypercellular, with a dense macrophage infiltrate. (B) Infiltrating population was confirmed as macrophages by immunohistochemistry to CD68. (C) Luxol fast blue stain demonstrating virtually total myelin loss. (D) Immunohistochemistry demonstrated relative preservation of axons; these were separated by infiltrating macrophages, and show irregularity, representing damage. (E) Immunohistochemistry to GFAP showing reactive astrocytes. (F) Immunohistochemistry to CD3 demonstrated sparse T cells (arrow). (G) A few CD79a-positive B cells were also present. Magnifications as shown on scale bars.
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F2
The biopsy findings of a macrophage rich lesion with severe myelin loss but relative axonal preservation suggested a demyelinating pathology (Figure 2).
Post-mortem neuropathology. (A) Coronal slice of cerebrum showing three irregular, cavitating white matter lesions (arrows). There is some dilatation ex vacuo of the ventricles, presumably secondary to white matter loss. (B) H and E stained section showing part of a lesion with preserved cortex above (star). (C) Luxol fast blue showing loss of myelin. (D) High power view of lesion stained with luxol fast blue shows total loss of myelin. (E) Neurofilament immunohistochemistry showing total axon loss in the center of a lesion. (F) Toward the lesion margin a few axons remain (arrows). (G) Up-regulation of amyloid precursor protein, upper left, with multiple axonal spheroids (arrow). (H) CD68 staining showing ameboid microglia, particularly in a perivascular location. Magnifications as shown on scale bars.
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F3
The findings were of a multifocal leukoencephalopathy, with severe loss of both axons and myelin (Figure 3).