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a brain tumor composed of medulloblasts.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
`A tumor consisting of neoplastic cells that resemble the undifferentiated cells of the primitive medullary tube; medulloblastomas are usually located in the vermis of the cerebellum, and may be implanted discretely or coalescently on the surfaces of the cerebellum, brainstem, and spinal cord; they comprise approximately 3% of all intracranial neoplasms, and occur most frequently in children; the neoplastic cells are compactly arranged, rounded or ovoid, with hyperchromatic nuclei and relatively scant cytoplasm, and lie in small and poorly defined groups, or, occasionally, in a pseudorosette pattern (Homer-Wright rosette). A type of primitive neuroectodermal tumor.
Farlex Partner Medical Dictionary © Farlex 2012
medulloblastomaPrimitive neuroectodermal tumor Neurology A malignant brain tumor that comprises ±1⁄4 of intracranial tumors in children and adolescents; it is most common at the midline of the cerebellum, and on the roof of 4th ventricle Clinical Presents with N&V, headache, ataxia, papilledema, nystagmus, irritability, lethargy, cranial nerve palsy, dizziness, altered vision Prognosis 2 yr-survival after relapse is 46% in those treated with salvage chemotherapy or RT, 0% in untreated Pts. See Brain tumor. Cf Glioblastoma.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
A tumor consisting of neoplastic cells that resemble the undifferentiated cells of the primitive medullary tube; medulloblastomas are usually located in the vermis of the cerebellum, comprise approximately 3% of all intracranial neoplasms, and occur most frequently in children.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
medulloblastomaA malignant brain tumour, most commonly affecting children and usually occurring in the CEREBELLUM or in the nearby roof of the FOURTH VENTRICLE.
Collins Dictionary of Medicine © Robert M. Youngson 2004, 2005