Primary intracranial solitary leptomeningeal glioma: a report of 3 cases.

Primary intracranial solitary leptomeningeal gliomas are exceedingly rare. We, therefore, performed a detailed clinical, radiological and pathological analysis to better characterize these tumors in 3 patients (33- and 72-year-old men and a 72-year-old woman). Two of the tumors were located in the frontal region and 1 in the temporal region. Magnetic resonance imaging revealed a well circumscribed large lesion (maximal diameter 4 - 6 cm) with peritumoral edema, mixed low- and isosignal intensity on T1-weighted images, hypersignal intensity on T2-weighted images and non-homogeneous contrast enhancement. External carotid angiography demonstrated a vascular supply to these tumors via branches of the middle meningeal artery. Gross total resection was achieved in all patients. The pathological diagnosis was glioblastoma in 2 patients and oligodendroglioma in 1. The MIB-1 nuclear labeling index ranged from 11.8% - 23.6% (mean 18.2%). Local tumor recurrence was documented in 2 patients after 8 and 11 months, respectively. The other patient with glioblastoma developed a metastasis to the femur 39 months after craniotomy. A definitive diagnosis can be made by careful radiological assessment and histopathological examination.