[Case of isolated neurosarcoidosis requiring differentiation from tuberculous meningitis]

A 62-year-old woman was transported to our hospital for management of generalized clonic seizures. Cerebrospinal fluid examination showed an increased monocyte-dominant cell count, high protein concentration, and low glucose concentration that was 17% of the plasma glucose concentration. Contrast-enhanced cranial magnetic resonance imaging revealed diffuse leptomeningeal enhancement with multiple nodular lesions. She underwent examinations that ruled out the following conditions: tuberculous meningitis, systemic sarcoidosis, malignant lymphoma, carcinomatous meningitis, and central nervous system vasculitis. On hospital day 13, dural and brain biopsies revealed neurosarcoidosis, for which steroid therapy was administered. Thereafter, imaging examinations showed marked improvement. Because isolated neurosarcoidosis is difficult to diagnose, early pathologic diagnosis may be essential.