A case report and review of the literature.

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare central nervous system neoplasm in which gliomatous tissue is diffusely identified in the subarachnoid space with no evidence of a primary intraparenchymal tumor. A 52-year-old man presented low back pain followed by sudden unconsciousness and had also cognitive dysfunction and meningeal sign. Examinations of cerebrospinal fluid (CSF) did not show malignant cells but increased protein and pleocytosis. Magnetic resonance (MR) imaging demonstrated diffuse leptomeningeal enhancement without any source of intraparenchymal lesion. Fluid-attenuated inversion recovery (FLAIR) also demonstrated individual diffuse high intensity area in the subarachnoid space. A biopsy disclosed wide spreading of anaplastic glial cells within the leptomeninges. He died 3 months later because of disease progression despite both radiotherapy and chemotherapy. Post-mortem examination identified PDLG and several neuropathological features of glioblastoma as well. Reviewing previous cases of PDLG instructs that this entity is rare, resembles meningitis in clinical pictures, usually occurs in a relatively younger population and has more progressive clinical course than the ordinary form of malignant gliomas.