Cerebellar mutism syndrome.

Since 1980, a growing number of pediatric patients with mutism following posterior fossa surgery have been recognized. This syndrome typically affects children and in rare cases young adults who become mute one or two days after tumor operation but do not show disturbances of consciousness or language comprehension. The disorder persists for 1 to 4 months. The pathogenesis is still unknown. Of 21 children who underwent surgery for large posterior fossa tumors between 1991 and 1995, 6 developed cerebellar mutism. Histologically the tumors were classified as astrocytoma WHO grade I, astrocytoma WHO grade II and ependymoma WHO grade III in one case and medulloblastoma WHO grade IV in three cases. Besides the clinical course, intraoperative findings and CT or MRI data are evaluated and discussed considering possible etiological hypotheses. Our own experience and also literature reviews suggest that the lesion of the cerebellar hemispheres might be the most important one of multiple factors causing cerebellar mutism. Generally the syndrome is transient. The diagnosis should not delay adjuvant therapy in patients with a malignancy.