[A case of multifocal fibrosclerosis presenting with chronic subdural hematoma].

Multifocal fibrosclerosis(MFS) is a rare disorder of unknown etiology, characterized by chronic inflammation with dense fibrosis and lymphoplasmacytic infiltration into the connective tissue of various organs. Recently, MFS was classified as IgG4-related systemic disease. In this paper, we report a 60-year-old man with no history of head injury presenting with chronic subdural hematoma(CSDH). After surgery, he complained of severe, continuous headache and persistent high-grade fever. Extensive evaluation, including ⁶⁷Ga scintigraphy suggesting inflammations in various organs, liver needle biopsy showing sclerosing cholangitis, and blood examination showing elevated serum IgG4 levels, led to the diagnosis of MFS. To our knowledge this is the first report of MFS causing CSDH. The mechanism of the formation of CSDH is presumed to involve reactive granular membrane together with exudative subdural collection caused by MFS, which gives rise to minor and repeated bleeding. In this case, oral corticosteroid therapy was dramatically effective in the treatment of the condition.