Primary diffuse leptomeningeal glioblastoma: Report of two cases.

Background: Primary leptomeningeal glioblastoma (PLGBM) is rare and not well understood. Case Description: Case 1: A 26-year-old woman with neurofibromatosis type 1 (NF1) sustained a headache. At presentation, the patient had unilateral abducens nerve palsy. Cerebral magnetic resonance imaging (MRI) detected subtle leptomeningeal enhancements along the brainstem and fourth ventricle, lacking an identifiable intraparenchymal mass. However, an MRI performed 2 months later revealed extensive leptomeningeal lesions over the cerebrospinal axes. Biopsy through a T9 hemilaminectomy led to the diagnosis of glioblastoma (GBM). The patient underwent chemoradiation therapy but died of disease progression 2 years after diagnosis. Case 2: A 78-year-old man presented with somnolence. The patient did not exhibit any focal neurological deficits. Cerebral MRI revealed diffuse leptomeningeal enhancement over the cerebrospinal axes. No intraparenchymal tumor was identified. Biopsy through craniotomy diagnosed GBM. Despite the commencement of chemoradiation therapy, the patient died of disease progression 45 days after diagnosis. Conclusion: PLGBM presents a diagnostic challenge for nonspecific clinical findings. For PLGBM patients complicated by NF1, an aggressive treatment strategy may be recommended for longer survival.