PMC5540643_01
Axial MRI FLAIR sequence shows increased signal in the right temporal (a) and left parieto-occipital (b) areas.
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F1
T2/FLAIR signal predominantly in the left parieto-occipital and right temporal lobes without abnormal contrast enhancement. These findings were thought to be most characteristic of acute disseminated encephalomyelitis (ADEM) or low-grade glioma (Figure 1).
Brain biopsy - Immunostain for CD68 highlights numerous positive cells consistent with macrophages. The presence of numerous macrophages and relative preservation of axons is suggestive of a demyelinating process (original magnification X200). Brain biopsy - Immunostain for SV40 shows positivity in large nuclei. The presence of SV40 positive nuclei is suggestive of a demyelinating process such as progressive multifocal leukoencephalopathy. SV40 is a DNA virus which belongs to the genus Polyomavirus. Other Polyomaviruses including BK and JC can be associated with kidney disease and demyelinating brain diseases (original magnification X200).
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F2
A subsequent brain biopsy showed the presence of numerous macrophages and relative preservation of axons suggestive of a demyelinating process (Figure 2). Immunocytochemical staining of tissue sections from the biopsy specimen were positive for SV40 antigen in nuclei, which was consistent with the diagnosis of PML (Figure 2).
Autopsy heart - Dense scar with multinucleated giant cell in the anterior myocardium (original magnification X200). B. Autopsy right lung apex - Multinucleated giant cell with asteroid bodies which are seen in granulomatous diseases such as sarcoidosis (original magnification X200). C. Autopsy mediastinal lymph node - Hyalinized lymph node with multinucleated giant cells (original magnification X100). D. Section of brain from autopsy - Luxol fast blue stain shows areas of demyelination (original magnification X20).
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F3
The heart contained dense scars in the myocardium with multi-nucleated giant cells (Figure 3). The respiratory system showed interstitial fibrosis in the bilateral apices with multi-nucleated histiocytes and giant cells present diffusely in the lung parenchyma, representing degenerated granulomas (Figure 3). There was mediastinal and hilar lymphadenopathy with hyalinized lymph nodes showing multi-nucleated histiocytes and giant cells similar to the findings in the heart and lungs (Figure 3). There was evidence of demyelination and some degree of axonal loss (Figure 3).