Clinical brain tumor of MRI

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Clinical brain tumor of MRI

• ????????
• 2007.04.20

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Case 1

• Clinical History
• 17-year-old female with a clinical suspicion of
  cerebellar mass.

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Your diagnosis is
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Radiologic Findings

• A T1W image (Fig. 1) shows a hypointense,
  approximately 7cm x 4cm mass in the right
  cerebellar hemisphere, with a moderate amount of
  mass effect on the 4th ventricle and cerebellum.
• The mass is hyperintense on the T2W image (Fig.
  3).
• The cystic portion of the mass has signal
  intensity similar to CSF on the T1W images and
  T2W images, but is hyperintense to CSF on the
  proton density weighted image (Fig. 2) due to
  increased protein content.
• Following Gadolinium administration, T1W images
  (Fig. 4-6) show intense homogeneous enhancement
  of a mural nodule in the superior aspect of the
  mass.
• Although septations within the mass show faint
  enhancement, the cystic portion of the mass does
  not show enhancement.

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Diagnosis

• Juvenile pilocytic astrocytoma.

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Discussion

• Cerebellar juvenile pilocytic astrocytomas are
  the most common infratentorial neoplasm in the
  pediatric age group.
• Although they commonly form well-defined lobular
  masses which contain cysts and a vascular mural
  nodule, they may occasionally present a solid
  mass without a cystic component and may simulate
  other pediatric posterior fossa masses.
• They have an increased incidence in type I
  neurofibromatosis.
• They have an excellent prognosis following
  complete resection.
• The differential diagnosis includes
  medulloblastoma and ependymoma in a child.

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Case 2

• Clinical History
• 3-year-old presents with headache and ataxia.

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Your Diagnosis is?
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Diagnosis

• Ependymoma.

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Findings

• Axial CT image demonstrates a right cerebellar
  and fourth ventricle mass which is somewhat
  higher in attenuation than the remaining brain
  parenchyma.
• In addition, there is marked dilatation of the
  temporal horns indicating hydrocephalus.
• Axial T1 and T2 weighted images as well as a
  sagittal image following the intravenous
  administration of contrast demonstrates an
  approximately 4 cm fourth ventricular mass with
  probable extension toward the outlets of the
  fourth ventricle.
• There is very little enhancement following the
  intravenous administration of contrast.

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Discussion

• Ependymomas are the third most common brain tumor
  in children and account for approximately 15 of
  posterior fossa malignancies.
• They classically arise from ependymal cells
  lining the fourth ventricle. Commonly, the tumor
  expands the fourth ventricle and extends through
  the foramen of Magendie and through the foramina
  of Luschka.
• The tumors are often calcified and may
  demonstrate a large cystic component.
• Inhomogeneous enhancement is usually seen.
  Because of their location, seeding throughout the
  subarachnoid space can be seen.
• Supratentorial ependymomas, however, are usually
  more aggressive and have a poorer prognosis.
• As stated above, ependyomomas are the third most
  common posterior fossa tumor in childhood behind
  juvenile pilocytic astrocytomas and
  medulloblastomas.

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Case 3

• History
• 10-year-old presented with 10 days of vomiting,
  unsteady gait, slurred speech, headache, and
  diplopia.

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Your diagnosis is
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Diagnosis

• Medulloblastoma (PNET).

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Findings

• A sagittal noncontrast T1W image (Image 1)
  reveals a mildly hypointense mass arising in the
  4th ventricle with expansion posteriorly to
  displace and distort the vermis.
• An axial T1-weighted image after contrast (Image
  2) demonstrates the loss of definition of the
  peripheral borders of the enhancing 4th
  ventricular mass.
• No additional abnormalities in the
  periventricular or subarachnoid space are
  identified.
• The mass is hyperintense to gray and white matter
  on an axial T2-weighted image (Image 3). There is
  a shunt under the right occipitotemporal scalp.

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Discussion

• Medulloblastoma represents about 25 of childhood
  intracranial tumors, with approximately 50
  presenting in the first decade.
• Medulloblastoma occurs only in the posterior
  fossa, although it has been grouped with
  histologically similar tumors arising elsewhere
  as a primitive neuroectodermal tumor (PNET).
• Medulloblastoma generally involves the 4th
  ventricle and vermis, with a lateral location
  more common in the desmoplastic variant and in
  older patients.
• On MR, medulloblastoma involves the 4th ventricle
  and vermis, although eccentric extension to
  involve the cerebellar hemispheres is not rare.
• It is nonspecifically hypo- to isointense on T1W
  images and hyperintense on T2W images.

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TEST

• What is the most common infratentorial neoplasm
  in the pediatric age group?

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QA
1.??Medulloblastoma?Ependymoma?Astrocytoma?
CT?????????? ? Medulloblastoma???????,??CT?????