Primary diffuse leptomeningeal gliomatosis simulating tuberculous meningitis

Three patients are reported on who presented with communicating hydrocephal us due to presumed tuberculous meningitis. Subsequent clinical deterioratio n despite antituberculous chemotherapy prompted reassessment with FD G-PET scanning and meningeal biopsy in one case and repeat CSF cytology with spec ial staining in the second. The third patient died and postmortem confirmed a diagnosis of primary diffuse leptomeningeal gliomatosis. In the first tw o patients, MRI of the entire neuraxis showed no evidence of a primary intr aparenchymal tumour. These cases emphasise the need for repeated reassessme nt in patients with culture negative lymphocytic meningitis. In addition, t his is the first report of FDG-PET scanning in leptomeningeal gliomatosis.