Purpose: The 3-year survival rate of pediatric patients with infiltrating brain stem gliomas (BSG) is < 10 %, Treatment involves local field radiation, and local failure has been the hallmark of recurrence, With therapeutic advances and improved radiographic monitoring, perceived and actual patterns of failure may change, We report patterns of recurrence in a group of patients with close follow-up, treated on an institutional protocol incorporating hyperfractionated involved-held radiation therapy and concomitant carboplatin, who have been uniformly staged and treated and have undergone MRI surveillance, Methods and Materials: From 1990 - 1995, 18 pediatric patients,vith BSG were treated on a Phase I-II trial of concurrent carboplatin and hyperfractionated radiotherapy, Eight had surgical procedures to document histology. Nine had hydrocephalus prior to death, All had pretreatment brain and spine MRIs, with and without gadolinium, that showed no other evidence of disease, Treatment consisted of 72.00 Gy involved-held hyperfractionated radiation therapy and dose-escalating concomitant carboplatin, Results: Fifteen children have had progression of disease (median PFS = 9 months); and 13 have died (median OS = 14 months), Fourteen of the 15 children with progression had local failures, 8 of whom had evidence of noncontiguous spinal (4) or intracranial (7) disease documented by MRI or autopsy, One child with local control developed an intracranial metastasis. None had clinical manifestations of leptomeningeal disease, Conclusion: Leptomeningeal dissemination occurred within 1 month of local progression in nearly 30 % of our patients and, overall, occurred in 50 % prior to death, This high incidence map reflect close MRT surveillance or a changing pattern of recurrence, Because the majority of leptomeningeal disease occurs in the setting of local progression, treatment efforts must be directed primarily toward local control, However, management of leptomeningeal dissemination at recurrence is of increasing concern. (C) 1998 Elsevier Science Inc.