Focal brain-stem astrocytomas causing symptoms of involvement of the facial nerve nucleus: long-term survival in six pediatric cases

Abstract

Six children with a history of isolated facial nerve dysfunction or dizziness and nausea were treated for brain-stem glioma between 1984 and 1992. Computerized tomography and/or magnetic resonance (MR) imaging showed a focal, uniformly enhancing mass involving the facial nerve nucleus of the pons. All patients underwent biopsy; the histological diagnosis was juvenile pilocytic astrocytoma in five cases. In the remaining case the biopsy was nondiagnostic, although the surgeon believed that the lesion was a glioma. Postoperatively, five patients underwent conventional focal megavoltage radiation therapy (180 to 200 cGy/day) over a period of 5 1/2 weeks to a total dose of approximately 5400 cGy. One child's family refused radiation therapy; she remained well and stable for 4 years, despite persistent facial weakness, and was eventually lost to follow-up review. Four irradiation-treated patients had complete resolution of their tumors on MR images and have had no evidence of neuropsychological or neuroendocrinological deficits during 4 1/2 to 8 years of follow-up evaluation. Patients whose neuroradiological studies show a lesion resembling those in this series should undergo biopsy and, if the histology of a low-grade tumor (in particular, a juvenile pilocytic astrocytoma) is confirmed, should then receive focal radiation therapy with conventional megavoltage dosages.