Evolution of Malignant Cerebellar Astrocytoma at the Site of a Treated Medulloblastoma: Report of two Cases

The authors report two unusual cases in which a malignant astrocytoma developed at the site of the excision of an earlier medulloblastoma. While the precise etiology of these astrocytic tumours was unproven, theories of the origins of the second tumours, particularly in relation to the basic nature of medulloblastomas, are discussed.