Between August 1987 and June 1994 we operated upon 30 consecutive children suffering from endophytic intra-axial tumors located in the pons and/or medulla oblongata. We present the clinical findings, neuroradiological aspects and histopathological results recorded in these cases. Diagnostic tests included clinical examinations, neurophysiological tests and neuroradiological imaging [magnetic resonance tomography (MRT) in all cases, often combined with cranial computer tomography (CCT)]. The diagnosis was confirmed by histopathological examination of the tumor material obtained by open surgical exploration in all cases. We conclude that a short history and more horizontal growth within the pons are more valuable predictors of the histopathology than differentiation between focal or diffuse growth patterns. MRT has little predictive value for histopathological diagnosis in intra-axial brain stem tumors.