PATH-84. Clinical diagnosis of primary diffuse leptomeningeal gliomatosis: two case reports and review of the literature

Primary diffuse leptomeningeal gliomatosis (PDLG) is a rare disease characterized by diffuse infiltration of the leptomeninges by neoplastic glial cells. PDLG occurs both in children and adults with no sex predilection. PDLG is very aggressive and fatal, with median survival reported ranging from 4 to 8 months. The most common symptoms and signs are headache, nausea, vomiting, papilledema, cranial nerve palsy, meningismus, seizures, and mental status alteration due to the increase in intracranial pressure. It is difficult to differentiate PDLG from infectious and inflammatory diseases such as meningeal tuberculosis, autoimmune meningitis, and sarcoidosis based solely on clinical course and radiological images. Cerebrospinal fluid examination shows non-specific findings in most cases, and cytology is usually negative. Therefore, many of the reported PDLG cases were initially diagnosed and treated as meningeal tuberculosis. If initial treatment is ineffective, biopsy must be performed promptly to confirm the diagnosis of PDLG, but the site must be selected carefully. Steroid therapy, ventricular drainage, and antiepileptic drugs have been used for the symptomatic treatment. A combination of craniospinal irradiation and chemotherapy has been reported to prolong the survival time in some patients. In this study, we presented the detailed clinical course of two cases of PDLG that occurred in a 21-year-old woman and a 67-year-old man. Literature review was also conducted to clarify the definition of PDLG and how to diagnose PDLG. Furthermore, we summarize the latest genetic analysis and treatment in the literature as well.