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{{Infobox_Disease |
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Name = {{PAGENAME}} |
Thanks for uploading '''[[:Image:CRIM0012.jpg]]'''. I noticed that the file's description page currently doesn't specify who created the content, so the [[copyright]] status is unclear. If you did not create this file yourself, then you will need to specify the owner of the copyright. If you obtained it from a website, then a link to the website from which it was taken, together with a restatement of that website's terms of use of its content, is usually sufficient information. However, if the copyright holder is different from the website's publisher, then their copyright should also be acknowledged.
Image = CompT.jpg|
Caption = CT scan, showing a tumorous mass in the [[posterior fossa]], giving rise to obstructive [[hydrocephalus]], in a six year old girl.|
DiseasesDB = 31105 |
ICD10 = |
ICD9 = |
ICDO = |
OMIM = 155255 |
MedlinePlus = |
eMedicineSubj = neuro |
eMedicineTopic = 624 |
eMedicine_mult = {{eMedicine2|ped|1396}} {{eMedicine2|radio|434}} |
MeshID = D008527 |
}}
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'''Medulloblastoma''' is a highly malignant primary [[brain tumor]] that originates in the [[cerebellum]] or [[posterior cranial fossa|posterior fossa]].
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Originally considered to be a [[glioma]], medulloblastoma is now known to be of the family of cranial [[primitive neuroectodermal tumor|primitive neuroectodermal tumors]] (PNET).<ref name="emed-medullo">George Jallo, MD, [http://emedicine.com/neuro/topic624.htm Medulloblastoma], eMedicine 2007.</ref>
==Image source problem with Image:CRIM0010.jpg==
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Tumors that originate in the cerebellum are referred to as [[infratentorial_neoplasms|infratentorial]] because they occur below the [[tentorium_cerebelli|tentorium]], a thick membrane that separates the [[cerebral hemispheres]] of the brain from the cerebellum. Another term for medulloblastoma is infratentorial PNET. Medulloblastoma is the most common cranial PNET.<ref>Chris Hinz, Deneen Hesser, [http://hope.abta.org/mdl Focusing On Brain Tumors: Medulloblastoma], American Brain Tumor Association 2006, ISBN 0-944093-67-1.</ref>
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Medulloblastoma is an invasive and rapidly growing tumor that, unlike most brain tumors, spreads through the [[cerebrospinal fluid]] (CSF) and frequently metastasizes to different locations in the brain and spine.
==Incidence==
[[Brain tumor|Brain tumors]] are the second most common malignancy among children 0-19 years of age, and of those, medulloblastoma is the second most common CNS malignancy.<ref name="seer">James G. Gurney, Malcolm A. Smith, Greta R. Bunin, [http://seer.cancer.gov/publications/childhood/cns.pdf CNS and Miscellaneous Intracranial and Intraspinal Neoplasms], SEER Pediatric Monograph, National Cancer Institute</ref> Medulloblastoma comprises less than 2% of CNS malignancies diagnosed in adults.<ref>[http://cbtrus.org/2005-2006/tables/2006.table12.pdf, Selected Primary Brain and Central Nervous System Tumor Age-Specific Incidence Rates], Central Brain Tumor Registry of the United States, 1998-2002.</ref>
Medulloblastoma has a bimodal incidence at the ages of 4-8 years, then in the early 20s and accounts for ~20% of childhood brain tumors. Males out of female 3:2 or 3:1 in many cases.
==Pathogenesis==
It is currently thought that medulloblastoma arises from cerebellar "stem cells" that have been prevented from dividing and differentiating into their normal cell types. This accounts from the varying histologic variants seen on biopsy. '''Rosette''' formation is highly characteristic of medulloblastoma and is seen in up to half of the cases.
Molecular genetics reveal a loss of genetic information on the distal part of chromosome 17, distal to the ''[[p53]]'' gene, possibly accounting for the neoplastic transformation of the undifferentiated cerebellar cells. Medulloblastomas are also seen in [[Gorlin syndrome]] as well as [[Turcot syndrome]]. Another research has strongly implicated the [[JC virus]], the virus that causes [[progressive multifocal leukoencephalopathy|multifocal leukoencephalopathy]].
==Clinical manifestation==
Symptoms are mainly due to secondary increased [[intracranial pressure]] due to blockage of the [[fourth ventricle]] and are usually present for 1 to 5 months before diagnosis is made. The child typically becomes ''listless'', with repeated episodes of ''vomiting'', and a ''morning headache'', which may lead to a misdiagnosis of gastrointestinal disease or migraine. Soon, the child will develop a ''stumbling gait'', ''frequent falls'', ''[[diplopia]]'', ''[[papilledema]]'', and ''sixth cranial nerve palsy''. ''Positional dizziness'' and ''[[nystagmus]]'' are also frequent and facial sensory loss or motor weakness may be present. [[Decerebrate]] attacks appear late in the disease.
Extraneural metastases to the rest of the body is rare, but usually only after [[craniotomy]].
==Diagnosis==
The tumor is distinctive on T1 and T2-weighted [[MRI]] with heterogeneous enhancement and typical ___location adjacent to and extension into the fourth ventricle.
Histologically, the tumor is solid, pink-gray in color, and is well circumscribed. The tumor is very cellular, many mitoses, little cytoplasm, and has the tendency to form clusters and rosettes.
== Treatment and Prognosis==
Treatment begins with maximal resection of the tumor. The addition of ''radiation'' to the entire neuraxis and ''chemotherapy'' may increase the disease-free survival. This combination may permit a 5 year survival in more than 80% of cases. The presence of desmoplastic features such as connective tissue formation offers a better prognosis. Prognosis is worse if child is less than 3 years old, inadequate degree of resection, or if presence of any CSF, spinal, supratentorial or systemic spread.
Increase intracranial pressure may be controlled with [[corticosteroids]] or a ventriculoperitoneal [[shunt_(medical)|shunt]]
{{main|intracranial pressure}}
==Notes==
<references/>
==References==
*Ropper, AH; Brown, RJ; ''Adams and Victor's Principles of Neurology'', 2005, McGraw Hill
*Eibl RH, Kleihues P, Jat PS, Wiestler OD (1994) A model for primitive neuroectodermal tumors in transgenic neural transplants harboring the SV40 large T antigen. Am J Pathol. 1994 Mar;144(3):556-64
==External links==
* Roger Packer M.D, [http://virtualtrials.com/medullo.cfm Medulloblastoma], Clinical Trials and Noteworthy Treatments for Brain Tumors 2002.
* [http://www.medulloblastoma.org Medulloblastoma support resources]
* {{Chorus|00905}}
[[Category:Neurology]]
[[Category:Neurosurgery]]
[[Category:Types of cancer]]
[[de:Medulloblastom]]
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