Pictorial lesson in CNS Tumours

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Pictorial lesson in CNS Tumours

• Dr H.K.Lord

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Anatomy Reminder
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• Malignant Brain Tumours

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Glioma Grading of Tumours
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Diffuse low-grade astrocytoma

• Axial T1-weighted MR image after gadolinium
  administration.
• A large left temporal tumour is present without
  any abnormal enhancement.
• The tumour is evident through its obliteration of
  normal sulci and gyri.

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Diffuse low-grade astrocytoma

• Axial T1-weighted MR image after gadolinium
  enhancement.
• Tumour is seen in the deep temporal region
  abutting the brainstem
• The temporal and occipital horns of the left
  lateral ventrical are dilated due to ex vacuo
  changes related to intervening treatment.

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Diffuse, low-grade astrocytoma

• Coronal section shows a tumour diffusely
  infiltrating the right frontal lobe.
• Gross determination of the tumour's boundaries is
  almost impossible, but the tumour is evident as
  an ill-defined area of enlargement with loss of
  distinction between the gray and white matter.

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Diffuse, low-grade astrocytoma

• In the white matter, there is a subtle
  infiltration of astrocytes with only slightly
  irregular features.

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Anaplastic astrocytoma grade III/IV

• Axial T2-weighted image at the level of the upper
  portion of the lateral ventricles.
• A large cystic tumour is present on the left with
  relatively little surrounding oedema The tumour
  shifts the midline to the right

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Anaplastic astrocytoma grade III/IV

• Microscopy reveals a densely cellular tumour with
  a high degree of cellular pleomorphism and
  increased mitotic activity.
• This tumor is distinguished from glioblastoma
  multiforme by the conspicuous absence of necrosis
  and endothelial proliferation.
• However, its high cellularity and pleomorphism
  raise suspicion that a larger sample size might
  have included areas exhibiting features of
  greater malignancy

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Two pathways to glioblastoma

• Glioblastoma can develop over 5-10 years from a
  low-grade astrocytoma (secondary glioblastoma)
• Or it can be the initial pathology at diagnosis
  (primary glioblastoma).
• The clinical features of glioblastoma are the
  same regardless of clinical route.

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GBM

• Axial T2-weighted MR image.
• The rounded tumour mass in the left frontal
  region is seen with extensive surrounding
  vasogenic oedema extending along white matter
  tracts.

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GBM Pathology

• Highly pleomorphic neoplastic cells, including
  giant cells, gemistocytic astrocytes and small
  anaplastic cells.
• Also typical are mitotic activity, proliferation
  of blood vessel endothelium and zones of
  necrosis.

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• Benign CNS Tumours

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Meningioma

• A large convexity meningioma severely displaces
  the underlying tissue downward and laterally,
  creating a midline shift and marked ventricular
  compression.

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Meningioma

• Whorl formation is often a valuable diagnostic
  feature. The whorls may be quite prominent, with
  cells tightly wrapping around one another in an
  'onion-skin' pattern.

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Craniopharyngioma

• The tumour may grow, extending into the third
  ventricle as in this midsagittal section, where a
  massive tumour fills the third ventricle.
• Benign growth from Rathkes pouch

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Craniopharyngioma

• Lateral skull radiograph demonstrates the radial
  calcifications of a large, suprasellar tumour.

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• Secondary CNS Tumours

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Metastatic spread

• Metastatic lung adenocarcinoma.
• Osseous metastases have expanded and destroyed
  several cervical vertebrae, with consequent
  flattening and distortion of the spinal cord. The
  subdural space was free of tumour

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Metastatic disease

• Metastatic breast carcinoma.
• The dura of this specimen has been reflected to
  reveal multiple subdural metastatic deposits.
• Note the lack of discernible infiltration of the
  subjacent brain by tumour.

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Systemic non-Hodgkin's lymphoma involving the CNS.

• Granular, hemorrhagic epidural and subdural
  tumour deposits.
• On microscopy, there would be extensive
  infiltration of the dura, with a large, subdural
  accumulation of tumour.
• Morphologic and immunophenotypic studies were
  diagnostic of a B-large cell lymphoma.

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• Childhood CNS Tumours

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Optic nerve astrocytoma

• CT scan of a 2-year-old girl with proptosis shows
  a large pilocytic tumor surrounding and involving
  the right optic nerve.

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Optic nerve astrocytoma

• Surgical specimen consisting of the globe and
  optic nerve from a 5-year-old girl with
  neuro-fibromatosis shows the tumour as a fusiform
  enlargement of the nerve.

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Olfactory neuroblastoma

• CT scan in a 19-year-old boy shows a mass filling
  the left nasal cavity.
• These tumours may grow either downward to fill
  the nasal cavity or upward through the the
  cribriform plate to enter the cranial vault.

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Medulloblastoma.

• Axial T2-weighted MR image at the level of the
  fourth ventricle.
• A large heterogeneous mass is present in the
  right cerebellum which compresses and displaces
  the fourth ventricles, in keeping with a
  medulloblastoma

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Rhabdomyosarcoma.

• In this specimen from a child, the tumour
  involves the pineal region and is associated with
  diffuse lepto-meningeal seeding.

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More Info

• More information available from
• i) Clinical SSC in Neuro-Oncology Dr HK Lord
• ii) http//www.braintumouraction.org.uk
• iii) http//www.cancerresearchuk.org/