[A case of IgG4-related hypertrophic pachymeningitis and leptomeningitis presenting with cognitive impairment].

A 68-year-old female was admitted to our hospital because of a right-sided headache since one year, an inability to perform housework, and a decrease in speech since March of that year. Upon admission, higher brain dysfunctions, including attention disorder, aphasia, and apraxia, were observed. Contrast-enhanced MRI revealed dural thickening in the bilateral frontal to parietal lobes and FLAIR imaging revealed high signal intensities in the bilateral frontal brain sulcus. Blood tests revealed a high IgG4 level (273 mg/dl). Dural biopsy revealed infiltration of IgG4-positive plasma cells into the tissue, and IgG4-related hypertrophic pachymeningitis was diagnosed. Administration of prednisolone resulted in resolution of the dural thickening, an absence of FLAIR imaging high signal intensities of the cerebral sulcus, and a considerable improvement of the higher brain dysfunctions. In patients with headache and higher brain dysfunctions, hypertrophic pachymeningitis should be considered in the differential diagnosis.