PMC3938990_01
PMC3938990_02
Macroscopy. (A) A coronal slice of the right hemibrain shows discoloration and granularity of the amygdala (arrow). A photomicrograph of the left hippocampus (B) shows diminished size and gray discoloration (arrow). (C) The cerebellum is unremarkable (left panel) and the substantia nigra (center panel) and locus coeruleus of the pons (right panel) show no significant pallor. There is an area of dark-brown discoloration at the junction of the tegmentum and basis pontis which corresponded to a nidus of bacteria-containing macrophages seen microscopically.
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F1
Circle of Willis. Coronal slices showed minimal generalized atrophy, mild atrophy of the amygdalae and hippocampi, and areas of discoloration and granularity were concentrated in the temporal lobes, amygdalae, hippocampi, putamena, and adjacent white matter (Fig. 1).
Microscopy and fine structure of T. whipplei encephalitis. There is parenchymal disruption, reactive astrocytosis, and macrophages with basophilic staining of intracellular material (A, hematoxylin and eosin (HE) x 400; B, HE x 1,000), and a granular staining pattern with periodic acid-Schiff (PAS) stain (C, x 1000). Gram stain shows predominantly pale blue staining of intracellular debris with occasional foci of strong gram-positivity (D, arrows: Gram stain x 1,000). Anti-T. whipplei antibodies highlight macrophages (E, T. whipplei immunohistochemistry x 1,000), and transmission electron microscopy reveals lamellar structures consistent with degraded bacteria (F, bar = 500 nm).
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F2
Sections of the hippocampi and amygdalae showed an inflammatory infiltrate containing monocytes, lymphocytes, plasma cells and CD68-immunoreactive macrophages admixed with large atypical reactive astrocytes and residual neurons (Fig. 2). Associated parenchyma showed disruption, gliosis, and neuronal loss (Fig. 2).