Leptomeningeal dissemination at diagnosis of pediatric low-grade neuroepithelial tumors.

The goal of this study was to describe the demographic, histologic, and prognostic features of children with low-grade neuroepithelial tumors (LGN) of the CNS presenting with leptomeningeal metastases (LM) at diagnosis. We identified 528 newly diagnosed LGN children, 13 (3%) of whom had LM at diagnosis. LM was defined by neuroimaging, clinical evidence, and/or biopsy. The charts were reviewed and patients contacted to validate the demographic data, treatment, and clinical status. The distribution of LM patients by primary tumor site was diencephalon, 5; cerebrum, 2; spinal cord, 3; brainstem, 2; and cerebellum, 1. Six of 8 patients with LM had durable objective responses to chemotherapy. The 5-year progression-free survival of patients with LM at diagnosis was 17%, compared to 85% (95% CI, 80%-91%) for those with localized LGN who had a gross total resection and 51% (95% CI, 44%-52%) for those with localized LGN who had less aggressive surgery ( P < 0.0001). Only 1 of these 13 LM patients died. The 5-year overall survival of the localized LGN group with a gross total resection was 97% (95% CI, 92%-99.9%), and that of the localized LGN group with less aggressive surgery was 88% (95% CI, 84%-95%) ( P = 0.004). The 3% frequency of LM at diagnosis is likely an underestimate since patients with newly diagnosed LGN were not routinely staged. We suggest that staging be considered in the following circumstances: diencephalic primary site, unexplained hydrocephalus, clinical features suggestive of LM, and before adjuvant therapy is initiated. The prognosis for children with LM at diagnosis is favorable, and its identification alters therapeutic strategies.