PMC7644338_01
CT head: (a) left frontal extra-axial lesion with patchy calcification and vasogenic oedema; (b) CT bone window setting showing osteopenia but no bony erosion or hyperostosis.
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As part of the investigative work-up of her confusion, she received a CT head which showed a left frontal extra-axial lesion with patchy calcification (Figure 1).
MRI brain. (a, b) Coronal and axial T1 postcontrast images showing pachymeningeal enhancement in the left frontal region and leptomeningeal enhancement in the left superior and middle frontal sulci, with vasogenic oedema. A nodular leptomeningeal enhancement is noted within the right parafalcine and superior frontal sulci with minimal underlying vasogenic oedema. There was no diffusion restriction. (c) Axial FLAIR image showing the extent of the vasogenic oedema.
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An outpatient MRI brain a month later demonstrated pachymeningeal and leptomeningeal enhancement bifrontally, with more marked changes on the left with underlying vasogenic oedema, and inflammatory opacification of the paranasal sinuses (Figure 2).
Histopathological examination from left frontal meningeal biopsy: (a) H&E stain demonstrating meningothelial whorls and associated chronic inflammation, (b) epithelial membrane antigen (EMA) stain confirming the meningothelial phenotype, and (c) H&E stain showing necrobiotic granulomata at the periphery of the lesion.
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Histopathological examination revealed a meningothelial neoplasm with a mitotic count of <4/10 high power fields and a low Ki67 labelling index (Figure 3).