Pathologic features of MOGAD

White matter pathology of MOGAD. (A) LFB/PAS stain and myelin protein CNPase immunohistochemistry (B) on consecutive sections indicate the perivenous (thick arrows) and confluent (arrows) demyelination that coexists in the subcortical white matter of a MOGAD biopsy. (C) H&E stain shows marked hypertrophic reactive astrocytes present in the white matter lesion and Creutzfeldt-Peters cells are occasionally noted (box). (D to I) Consecutive sections: (D) KiM1P immunohistochemistry indicates extensive microglia/macrophage infiltration in the white matter with no obvious border. The blue dotted lines contour the demyelinating lesion (E) with relative preserved axons (F). The loss of minor myelin protein MAG (G) and MOG (H) are equal. AQP4 is preserved in the lesion (I). (J and K) Consecutive sections. Preferential MAG loss (J, M) with relative MOG preservation (K, N) is seen in a single MOGAD case. (L) Mild axonal damage characterized by axonal spheroid (indicated with dashed arrows) is present in the demyelinating lesions. (O) Apoptotic oligodendrocytes with condensed nucleus (highlighted in the box) are seen in the lesions.
Scale bars in A, B, D to K = 200 micrometer. Scale bars in C, L, and O = 20 micrometer.