Isolated intracranial Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy).

SUMMARY Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) rarely affects the intracranial region without involvement of other sites. We report the case of a 68-year-old woman with isolated Rosai-Dorfman disease of the frontal dura. She presented with a new onset seizure. Initial MR imaging showed subtle mild change in the left frontal region. During the ensuing 8 months, a dural mass made its symptomatic and definite MR imaging appearance in the same region. No extracranial lesion was present.