PMC8141553_01
Histopathological findings from the case study. (A) Substantia Nigra. H&E. Disintegration of pigmented neurons, with Lewy bodies in two of those remaining (center and lower left). Bar = 100 microns. (B) Frontal cortex. H&E. A Lewy body is seen in the central neuron as a perinuclear region of increased eosinophilia (arrow). Bar = 20 microns. (C-E) Immunohistochemistry for alpha-synuclein. (C) Substantia nigra pars compacta. Inclusions are seen in cell bodies and neurites. Bar= 200 microns. (D) Hilus (CA3) of hippocampus. Bar = 50 microns. (E) Bielschowsky stain, hippocampus. Central neuron contains a Lewy body. Bar = 10 microns.
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F4
Microscopically, nigral and cortical Lewy bodies, were seen with hematoxylin and eosin stain (H&E, Figures 4A,B). Immunohistochemistry (IHC) for alpha-synuclein (clone 42, BD Transduction Laboratories) showed numerous immunoreactive Lewy bodies and fibers in substantia nigra, hippocampal formation and neocortex, Figures 4C-E).
Detection of amyloid plaques in the patient's CNS. (A) Amygdala and rostral hippocampus, entorhinal cortex, and transentorhinal cortex. AT8 immunohistochemistry with Verhoeff myelin counterstain. BAR = 2 mm. (B) Rare cortical neuritic plaque in middle frontal gyrus. AT8 with Verhoeff myelin counterstain. BAR = 20 microns. (C) Bielschowsky stain of CA1 and subiculum demonstrates numerous amyloid plaques. Bar = 1 mm. (D) Bielschowsky stain of frontal cortex. Amyloid plaques predominate; rare neuritic plaques are also present (arrow). Bar = 100 microns.
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F5
IHC for hyperphosphorylated tau (monoclonal antibody AT8; ThermoFisher) revealed intense staining of many limbic neurofibrillary tangles and neuropil threads (Braak stage 2-3, Figure 5), and of occasional neurofibrillary tangles in neocortex, but senile plaques were extremely rare, and each contained only a few fibrils (Figure 5).
Immunohistochemical staining for microglia. (A) Frontal cortex stained for Iba-1 (brown) and CD68 (black). Most microglia in this field contain large deposits of CD68 immunoreactivity and shirt, thick processes, indicating activation. By contrast, occasional surveilling microglia, are also present. The black box surrounds two such cells, whose somas and long, fine processes are apparent in the inset. (B) Spinal cord stained for CD163. CD163 is expressed by resident perivascular macrophages, which are normally present, but also by macrophages derived from circulating monocytes. Bar = 100 microns for (A,B). Inset is photographed at three times greater magnification in a stack spanning the thickness of the tissue at 0.25-micron intervals. The "Deep Focus" feature of Neurolucida 360 (MBF Bioscience) was used to combine the best focused objects from each layer of the stack into a single layer.
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F6
Iba-1 (Wako), CD68 (clone KP1, Dako), and CD163 (clone EDHu-1; Bio-Rad) showed moderate numbers of activated microglia and large numbers of macrophages in hippocampal formation and spinal cord (Figure 6). In summary, we see DLB accompanied by features of Alzheimer's disease, a common presentation.