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case_images: PMC10184201_02
case_images: Non-injected cerebral CT showing an iso to hyper dense, extra-axial left frontal and right parieto-occipital processes.
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case_images: Tomography (CT) revealed bifocal hyperdense and compressive extra-axial masses with perilesional edema in the right parieto-occipital region and the left frontal region. These masses produce a mass effect on the lateral ventricles and the middle line (Figure 1).
case_images: (a) Axial FLAIR magnetic resonance imaging showing expansive bifocal lesions, isointense on FLAIR with mass effect and vasogenic type edema (arrow); (b) Iso intense signal on T2; (c) Axial gadolinium-enhanced image; and (d) Axial sequence diffusion in b1000 revealing no restriction of diffusion.
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case_images: Gadolinium-injection demonstrated a strong and homogeneous enhancement (Figure 2).
case_images: (a) Macroscopic appearance of the mass; (b) Histologically, the lesion is constituted of large histiocytes having an eosinophilic and foamy cytoplasm (Hematoxylin-Eosin x20); (c) Many images of emperipolesis have been observed (arrow, Hematoxylin-Eosin x40); and (d) Note an inflammatory infiltrate rich in plasma-cells (Hematoxylin-Eosin x40).
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case_images: Macroscopically, the lesion was firm; greyish-white and lobulated (Figure 3a). Many images of emperipolesis were observed, that were highly suggestive of a Rosai-Dorfman disease (Figure 3).
case_images: At immunohistochemistry, histiocytes express S-100 protein (a) and CD163 (b).
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case_images: Immunostaining for BRAFV600E was negative (Figure 4).