Radiological and clinical findings of isolated meningeal Rosai-Dorfman disease of the central nervous system.

Rosai-Dorfman disease (RDD) with isolated central nervous system (CNS) involvement is an extremely rare disease. Most RDD of the CNS present as dural-based mass mimicking meningioma and other common lesions, which makes preoperative accurate diagnosis of great difficulty. We searched the pathology database in our hospital and 3 cases of RDD with isolated CNS involvement were finally included in our study. Radiological and clinical findings of these three cases were retrospectively analyzed. The lesions of 2 cases were dura-based against the cerebral convexity, presenting as a sheet-shaped thickened dura mater, another case was located just across the cerebral falx, the dural display in the center was intact. The 3 cases showed low signal intensity on T2-weighted image, obviously enhanced, significantly surrounding edema and finger-like protuberance but no invasion of the brain parenchyma or no sign of hyperplasia or sclerosis of the surrounding cranial bones. In conclusion, when we come across a disease that mimicking meningioma, especially when it manifests as the above radiological features, we should considered it might be a kind of proliferative disease of the meninges, such as RDD.