CD68 and sinus histiocytosis with massive lymphadenopathy: From a neuropathological lens, correlating emperipolesis with S100 or CD68 co-expression and, when available, negative Langerin remains critical to distinguish IC-RDD from meningioma, inflammatory pseudotumor, and Langerhans-cell lesions in small intracranial samples [2, 3, 101, 102].