Figure 3. Initial brain biopsy and autopsy microscopic findings.

Initial brain biopsy on day 2 of the right frontal region showed acute cerebritis. There was a marked acute inflammatory cell reaction most consistent with an acute infectious process noted in lower (A) and higher (B) magnification. The neutrophil predominance was determined to be consistent with a pyogenic process, although the Gram stain was negative. Silver stain was also negative for fungus. There was no neoplasm, granulomatous inflammation, or vasculitis present. (C, D) Hematoxylin & eosin stain at autopsy showed punctate, ring-shaped foci of perivascular hemorrhage and edema, localized to the white matter. This was surrounded by inflammation with a predominantly macrophage reaction in the right and left orbital frontal areas as well as right frontal-parietal sections. (E, F) Trichrome stain confirmed fibrinoid necrosis in multiple vessels in the right orbital frontal and frontal-parietal areas. There was no lymphocytic infiltration and no microglial nodules as seen in vasculitis and viral encephalitis, respectively. There was no inflammation in the vessel walls. Thromboemboli, viral cytopathologic effects, foreign abscesses, and granulomas were not seen.