Brain Pathology Case of the Month - September 2019

Contributed by Alejandro Perez, MD1, Gustavo C. Roman, MD2, Suzanne Z. Powell, MD1, Ron Fisher, MD3, Andreana L. Rivera1, MD, Joseph C. Masdeu, MD2, and Matthew D. Cykowski, MD1
1Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
     2 Department of Neurology, Houston Methodist Neurological Institute, Houston, TX, USA
     3 Department of Radiology, Houston Methodist Hospital, Houston, TX, USA


A 70-year-old man presented with a 10-month history of worsening cognition, speech impairment, ataxia, and dysphagia, as well as periodic episodes of brachial dystonia, choreiform movements, and facial grimacing. EEG studies were negative. MRI studies, including arterial spin labeling, showed only hyperperfusion of the right mesial temporal lobe. FDG-PET showed diffuse cortical hypometabolism (Figure 1A, white arrows) and relatively increased metabolism in the amygdala (Figure 1A, yellow arrows) and striatum (Figure 1A, orange arrow) bilaterally. Imaging studies of the chest, abdomen, and pelvis were negative. Despite therapy, the patient's disease proved refractory and he expired. A brain-only autopsy was performed 16 months following his initial presentation.


H&E-stained sections from the brain autopsy showed reactive astrogliosis, including bizarre, multinucleated astrocytes in the amygdala (Figures 1B, 1C, and 1D). Within amygdala, microglial activation was present and there were numerous CD4+, perivascular T-cells (Figures 1E and 1F). No cytoplasmic inclusions were identified by H&E stains and immunohistochemical studies for tau, p62, TDP-43, and alpha-synuclein were negative. No viral inclusions, foci of neuronophagia, or microglial nodules were identified. Nissl-stained sections showed conspicuous neuronal loss in basolateral and corticomedial amygdala and GFAP staining highlighted a very sharp demarcation between involved regions (e.g., basolateral amygdala, subiculum) and adjacent regions on the same slide (occipitotemporal cortex). Double-labeling immunofluorescence for astrocytes and vessels in amygdala and subiculum (Figure 1G) highlighted an intimate relationship of the reactive astrocytes and their foot processes to the perivascular space. What is your diagnosis?


International Society of Neuropathology