| neuroectodermal tumour, primitive | A malignant brain tumour sharing common features and biologic properties with medulloblastoma. Some pathologists and clinicians use the terms interchangeably: they both can disseminate throughout the nervous system and, in some cases, systemically. most lesions arise from the posterior fossa in children under five years of age. The tumour often produces hydrocephalus and symptoms of increased intracranial pressure. Papilledema is often present. (12 Dec 1998) |
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| neuroectodermal tumours | Malignant neoplasms arising in the neuroectoderm, the portion of the ectoderm of the early embryo that gives rise to the central and peripheral nervous systems, including some glial cells. (12 Dec 1998) |