PMC5843104_01
(a) T2-weighted (T2W), (b) fluid-attenuated inversion recovery, (c) T1-weighted (T1W) and (d) T1W post-contrast transverse images of the brain at the level of the third ventricle. The cat's left is on the right. Symmetric ventriculomegaly is apparent (*). There is poor white matter/grey matter distinction owing to diffuse hyperintensity of the white matter on T2W sequence. Marked cortical atrophy and widening of the cerebral sulci are visible (black arrow). Generalised, even calvarial hyperostosis is noted (white arrow)
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T2W signal intensity of the cerebral white matter was visible, with consequent decrease in the distinction between the white and grey matter (Figure 1).
T2-weighted sagittal image of the brain. Moderate dilation of the third and fourth ventricles is apparent. Hyperostosis of the osseous tentorium cerebelli and calvarium is visible (black arrow). There is mild widening of the cerebellar sulci (<) due to cerebellar atrophy
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Generalised and marked thickening of the calvarium and osseous tentorium cerebelli was visible (calvarial hyperostosis) with reduction of the fat signal of the diploe (Figure 2).
(a) Gross appearance of fresh cross section of the brain at the level of the hippocampus showing moderate atrophy with widening of sulci. (b) Hippocampus, cornu ammonis with pyramidal neurons (arrows) showing intracytoplasmic botryoid deposits of eosinophilic glassy material often associated with marginalisation of nuclei (inset). (c-e) Intracytoplasmic deposits are markedly positive to (c) Luxol fast blue, (d) moderately positive to periodic acid-Schiff stain and (e) red stained with Masson's trichrome stain. (f) Pyramidal neurons show green autofluorescence when observed under the fluorescent microscope (excitation 465-495 nm). (g-i) Transmission electron microscopy of occipital cortical neurons showing (g) membrane-bound material composed of (h) small curvilinear lamellar stacks and (i) electron-dense variably sized granular material morphologically consistent with lipofuscins
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Grossly, the meninges were diffusely moderately thickened and the brain showed moderate diffuse and bilateral cortical atrophy with narrowing of gyri and widening of sulci (Figure 3a). All cerebral areas examined showed mild-to-moderate gliosis and moderate loss of neurons (more severe in cortical areas) with numerous neurons distended and enlarged by botryoid, palely acidophilic to glassy cytoplasmic inclusions (Figure 3b), with frequent marginalisation of nuclei. Intracytoplasmic vacuoles resulted markedly positive to Luxol fast blue stain (Figure 3c), moderately positive to periodic acid-Schiff (Figure 3d) and stained red with Masson's trichrome (Figure 3e). When observed under a fluorescent microscope (excitation 465-495 nm) the cytoplasmic material showed green autofluorescence (Figure 3f). Ultrastructural examination of the intracytoplasmic neuronal deposits in the occipital cortex showed electron-dense, membrane-bound material (Figure 3g) composed of small curvilinear lamellar stacks (Figure 3h) and electron-dense, variably sized granular material (Figure 3i), consistent morphologically with previously described intra-neuronal lipofuscins in cats.