Immunohistochemistry Case 1 (A,C,E,G) and Case 2 (B,D,F,H). (A-B) There are HLA-DR positive reactive microglial cells but the vacuolated cells are negative. (C-D) The immunoreactivity with synaptophysin is strong in Case1 (C), while the vacuolated cells are only moderately positive in Case 2 (D), possibly due to overfixation. (E-F) There is strong HuC/HuD immunoreactivity in the vacuolated cells, as well as in a few round nuclei. (G-H) The p62 highlights the lesion by diffuse cytoplasmic labelling of the large vacuolated cells. Scale bars = 100 μm.