A case report of meningeal Rosai-Dorfman disease associated with IgG4-related disease.

Objective: Rosai-Dorfman disease is a rare entity that has been described as lymphadenopathy in young patients. Extranodal forms of this disease have been previously observed. The etiology of Rosai-Dorfman disease remains unknown, relationships with the IgG4-related sclerotic disease have been detected. Herein, a rare case of Rosai-Dorfman disease with meningeal involvement and IgG4-related sclerotic disease is reported.

Methods: A meningeal biopsy in a 35-year-old woman who had a 6-month history of intermittent headache was performed after MRI examination showing diffuse leptomeningeal enhancement without cerebral parenchymal involvement.

Results: A mixed infiltration of lymphocytes, plasma cells, and histiocytes exhibiting emperipolesis was identified. The stroma was fibrous. Immunohistochemical analysis revealed a high number of IgG4-positive plasma cells and a rate of IgG4/IgG-positive plasma cells higher than 50%.

Conclusions: The pathological results in this patient with meningeal infiltration are suggestive of Rosai-Dorman disease associated with IgG4-related disease. This observation further confirms the link between these two entities.