Semithin sections and electron microscopy. Case 1 (A-D). (A-B) Conspicuous vacuolar changes in the neuronal cells and the neuropil-like background. (A) Mild accumulation of small round cells is noted at the edge of the nodule. (C-D) Electron microscopy reveals non-membrane bound vacuolation. (D) Small vacuolated areas within the cisterns of the endoplasmic reticulum are also noted in the neuron. Case 2 (E-F). The vacuolar changes are similar those seen in Case 1 although the less well-preserved due to post-mortem changes. (A-B, E - semithin sections stained with Toluidine blue). Scale bars: A, B, E = 25 μm; C = 5 μm; D, F = 20 μm.