Rosai-Dorfman disease (RDD) is an idiopathic proliferation of histiocytes that affects the lymph nodes. Central nervous system involvement in the absence of nodal disease is extremely rare. On neuroimaging studies, intracranial RDD appears as solitary or multiple well-circumscribed, dura-based lesions. The authors report on two cases of RDD with locally aggressive features including dural sinus invasion, which to their knowledge has never before been described. A 60-year-old woman presented with progressive dizziness and vertigo that had lasted for 1 week. Cranial computerized tomography and magnetic resonance imaging revealed an extraaxial homogeneous lobulated enhancing mass involving the right occipital lobe and the right cerebellar hemisphere. Invasion of the right transverse sinus was identified on a cerebral digital subtraction angiogram. A 59-year-old man with no prior medical illness experienced progressive weakness of both upper extremities and a partial complex seizure. Magnetic resonance imaging of his brain revealed a well-circumscribed enhancing mass in the left frontal lobe with extension to the right frontal lobe and invasion of the superior sagittal sinus. Both patients underwent resection of their brain masses. Pathological studies identified the disease as RDD in both patients.