Malignant hemispheric tumors in childhood.

Sixty-four malignant hemispheric tumors in children less than 15 years old were treated in the pediatric neurosurgical department of the Hôpital des Enfants Malades between 1970 and 1989. (1) These tumors evolved rapidly in most cases. However the pre-operative evolution in 20% of the patients had a duration of more than 6 months, which favors the hypothesis that at least one-fifth of these tumors result from malignant transformation of a benign lesion. This observation should prompt neurosurgeons to operate on all benign hemispheric tumors as soon as they are diagnosed. (2) Five of the 64 patients had two successive malignant diseases. In four cases the other malignant disease was an acute lymphoblastic leukemia. (3) Among the malignant hemispheric tumors, the grade III and IV astrocytomas had a dismal prognosis. As it is known from previous studies that grade I and II astrocytomas have a good prognosis in children, it can be concluded that grading these tumors is essential. By contrast, almost one out of two patients with malignant ependymoma was alive 5 years after treatment. This implies that the grading of ependymomas is of modest prognostic values. (4) The harmful effect of radiotherapy was evaluated by comparing the functional outcome of children operated for a benign hemispheric tumor to that of children operated and irradiated for a malignant hemispheric tumor.