Meningeal lesion in the frontal convexity in a man with a steroid-responsive cavernous sinus syndrome due to Rosai-Dorfman disease (histological sections)

(A) At low magnification (H&E staining, 10x), there is fibrous and thickened dura mater (blue arrow) with extensive superficial infiltration by histiocytic cells (black arrow). (B) At intermediate magnification (H&E staining, 20x), there is extensive superficial meningeal infiltration by histiocytes (arrow); absence of cell atypias, malignant cells or meningothelial neoplasia. (C) Immunohistochemical staining for CD68 shows diffuse positivity in lesion cells, confirming the histiocytic aspect. (D) Immunohistochemical staining for S100 shows focal positivity in lesion cells, confirming the histiocytic aspect. Other reactions performed were negative: CD1a and ALK (not shown).

(Source: Nóbrega PR, Rodrigues PG, de Sousa Pereira I, et al. Steroid responsive cavernous sinus syndrome due to Rosai-Dorfman disease: beyond Tolosa-Hunt syndrome--a case report. BMC Neurol 2021;21[1]:264 Creative Commons Attribution 4.0 International [CC BY 4.0] license, creativecommons.org/licenses/by/4.0.)