The first case of glioblastoma multiforme of the cerebellum with extraneural metastasis is presented, and the literature on the postoperative extraneural spread of neuroectodermal tumors is reviewed. It is thought that an open dura mater at the operative site increases the contact of tumor cells with extrameningeal tissues, where lymphatic and vascular invasion can take place. Every effort should be made to close the posterior fossa dura mater after resection of a malignant neoplasm.