"Right parietal brain biopsy": Multiple pieces of soft tan tissue up to 5mm
Paraffin sections show fragments of cerebral cortex and white matter. Cortex is unremarkable. The white matter is densely infiltrated by foamy macrophages containing granular PAS+/Luxol Fast Blue positive material consistent with myelin breakdown products. Prominent reactive astrocytes are scattered among the macrophage population. T lymphocytes, predominantly CD8+, cells are scattered among the macrophage cell polulation. Smaller numbers of CD4+ T lymphocytes are also present. Macrophages and activated microglia show strong surface expression of MHC Class I antigen. Luxol Fast Blue staining shows loss of myelin and Bodian silver impregnation shows axonal fragmentation and formation of axonal spheroids indicating recent axonal injury. The overall features are of inflammatory demyelination. No viral inclusion bodies are identified There is no evidence of tumour.
Immunostaining for SV-40/JC-virus is NEGATIVE
"Right parietal brain biopsy": Inflammatory demyelination with features favouring plaque demyelination rather than ADEM.