Incidence and patterns of neuraxis metastases in children with diffuse pontine glioma

Purpose: We performed a retrospective study of patients with diffuse pontine glioma (DPG) who suffered neuraxis metastasis (NM) and characterized the incidence, clinical features, radiologic findings, and patterns of disease dissemination. Methods: Magnetic resonance imaging (MRI) of brain and spine was used to assess NM. Some patients also underwent magnetic resonance spectroscopy (MRS) (6 patients) and fluorodeoxyglucose positron emission tomography (FDG-PET) scans (13 patients) to further evaluate areas of metastatic disease. Three patients had histologic confirmation of disease at the site of NM. Results: Between 1986 and 2003, 18 of 96 patients (17.3%) with DPG developed NM. The median age at diagnosis was 8 years (range, 4-17). All patients had adjuvant chemotherapy and/or focal radiotherapy at diagnosis. The NM occurred at a median of 15 months from diagnosis of DPG (range, 3-96). Three patterns of NM were seen on MRI of brain and spine in these patients; 8 (39%) had parenchymal (PM), 4 (22%) leptomeningeal (PM), 2 (11%) subependymal, and in 5 a combination of two or more patterns. The MRS and FDG-PET scan of suspected areas of metastatic disease was consistent with tumor in 6 of 6 and 12 of 13 patients who underwent these procedures respectively. Three patients also had histologic confirmation of malignant glioma at the site of NM. Despite salvage therapy, all 18 patients have died of disease at a median of 5 months (range, 0.5-20) from diagnosis of neuraxis spread. Conclusion: Our study emphasizes the need for screening patients with DPG for NM at the time of recurrence.