Central Nervous System 9. Tumors * * * * USAULLY bilaterally

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Central Nervous System9. Tumors
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• INTRACRANIAL TUMORS (ICTS)
• Primary or Metastatic
• Occur with equal frequency in adults, but in
  children primary tumors are far more common.
• Primary ICTs account for
• 2 of cancers in adults
• 20 of all cancers in children.
• In children 70 of ICTs arise in ? Posterior
  fossa (infra-tentorial). as
• In adults 70 of ICTs arise in ?
  Supra-tentorial.
• Because of its location, a benign ICT may have
  fatal malignant effects.
• Malignant ICTs spread by
• Direct infiltration of adjacent tissues
• May disseminate within the CNS via CSF.
• Gliomas account for 60 of primary ICTs
• Meningiomas for 20 all others 20.
• All CNS tumors behave as malignant clinically .
  Limited space

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The unique features of CNS tumors ICP 1. CNS
tumors- lt 2 of all malignant tumors. They grow
in a unique environment the intracranial
space. 2. The intracranial contents -
incompressible Brain and blood contained within a
rigid unyielding bony structure. 3. Intracranial
pathologies (tumors, abscess, hematoma,
infarction, edema, etc.) eventually produce life
threatening increase of the intracranial-pressure
ICP.
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Cytologic origin of CNS tumors

• Neuro-ectodermal most important are the
  Gliomas
• Mesenchymal most frequent ones are the
  Meningiomas
• Ectopic tissues from tissues displaced during
  embryogenesis Ex., Dermoid cyst
• Retained embryonal structures various cysts
  Paraphyseal cyst
• Metastases Lung, Breast, Melanoma, etc. in 50
  of cases

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Neuro ecto - dermal tumors

• Glial cells
• astrocytes (A) - Astrocytoma
• Oligodendroglial cells - Oligodendroglioma
• Ependymal cells Ependymoma
• Neurons - Gangliocytoma

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Incidence of brain tumors
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Seen in kids with increased cellularity
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What is benign and malignant in case of CNS
tumors?
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ASTROCYTOMAS

• Account for 80 of primary ICTS in adults
• MC in the cerebral hemispheres
• MC Symptoms headaches, seizures, focal
  neurologic deficits ( usually in the anterior or
  middle)
• Low-grade Astrocytomas
• Gross
• Poorly defined gray-white infiltrative tumors.
• Histology
• Hypercellularity astrocytic nuclei of mild
  degree of atypia astrocytic processes ?
  fibrillary background fingers of astrocytes

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Low-grade Astrocytomas

• Pilocytic Astrocytomas
• MC in the cerebellum of children young adults
  and less commonly in the optic nerve,
  hypothalamic region or cerebral hemispheres
• Morphology
• Cystic, with a tumor nodule in the wall of the
  cyst.
• Composed of bipolar astrocytes, with long
  hair-like processes, Rosenthal fibers
  Micro-cysts calcification good prognosis
• Grow very slowly (some patients have survived for
  gt40 yrs after incomplete resection) have an
  Excellent prognosis
• DD - not to confuse with low grade Fibrillary
  Astrocytoma

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Grade I. tumor pilocytic astro
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Pilocytic Astrocytoma
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Pilocytic Astrocytoma
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Pilocytic Astrocytoma
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Rosenthal fibers
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Gr. II. Astrocytoma
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Gr. II. astrocytoma
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Gr. III. astrocytoma
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Gr. III. astrocytoma
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Gr. III. Astrocytoma
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Gr. IV. astro GBM
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Gr. IV. astro GBM
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Gr. IV. astro GBM
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GBM necrosis/pseudo-palisade
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GBM pleomorphic cytology
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Gr. IV. Astro GBM
Die directly
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OLIGODENDROGLIOMA

• Comprise 5 -15 of Gliomas
• Arise in the cerebral white matter
• MC in the 4th 5th decades
• Gross
• Well circumscribed, gelatinous, gray masses, with
  foci of hemorrhage calcification.
• Histology
• Sheets of cells with rounded nuclei surrounded by
  a halo of clear cytoplasm (fried egg appearance).
  
• There is often a delicate network of capillaries
  scattered foci of calcification (psammoma
  bodies)( seen in thyroid, CNS, kidneys etc).
• Grows slowly, presents commonly with seizures,
  prognosis is better than Astrocytoma, average
  survival is 5-10 yrs (with modern therapeutic
  approaches

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Oligodendroglioma
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Oligodendroglioma
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Oligodendroglioma
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Oligo-Astrocytoma
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EPENDYMOMA

• Arise from the Ependymal lining of the ventricles
  or the central canal of the spinal cord
• Arise in the
• Fourth ventricle in children young adults
• Spinal cord in the middle aged.
• Morphology
• Highly cellular, tumor cells have regular nuclei
• May exhibit epithelial features with formation of
  rosettes (Flexner) or canals, also
  perivascular pseudo-rosettes (homer )
• Most tumors are well differentiated
• 4th ventricle tumors
• May cause hydrocephalus, usually cant be
  completely removed
• CSF dissemination may occur
• Average survival is 4 yrs

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Myxo-papillary Ependymomas

• Arise in the filum terminale of the spinal cord
• Prognosis depends on completeness of surgical
  excision

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Ependymoma
Rosettes perivascular Pseudo-rosettes
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MEDULLOBLASTOMAS

• Second MC ICT of childhood (after Astrocytomas).
• Occurs exclusively in the cerebellum.
• Derived from fetal external granular layer of
  cerebellum.
• Grows rapidly occludes CSF flow ?
  hydrocephalus.
• Seeds through CSF ? implants around the spinal
  cord cauda equina (need irradiation of the
  whole Neuraxis).
• Histology
• Extremely cellular, anaplastic, small round or
  carrot-shaped cells with hyperchromatic nuclei, ?
  N/C, may form Homer-Wright pseudo-rosettes
• Highly malignant, yet radiosensitive 5-yr
  survival 75.

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Medulloblastoma
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Medulloblastoma
Homer-Wright pseudo-rosettes
carrot-shaped cells
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MENINGIOMAS

• Usually Benign slow-growing tumors of adults, F/M
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• Originate from meningothelial cells of the
  arachnoid.
• Usually solitary ( multiple meningiomas ? NF2 )
  
• Morphology
• Firm rounded masses, adherent to the dura and
  compressing the underlying brain (no
  infiltration).
• Histologic variants include
• Syncytial, fibroblastic, transitional,
  Psammomatous papillary (? propensity to recur).
• Malignant Meningioma is very rare
• Infiltrates the underlying brain, shows marked
  nuclear atypia, ? mitoses, foci of necrosis.
• Other rare sarcomas of meninges include
• Hemangiopericytoma, malignant fibrous
  histiocytoma Fibrosarcoma.

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Meningioma
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Meningioma
Syncytial
Psammomatous
Epithelial Membrane Antigen
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NERVE SHEATH TUMORS

• 1. Schwannomas
• Benign tumors of Schwann cells
• MC in the vestibular branch of the VIII CN at the
  cerebello-pontine angle (acoustic neuroma) ?
  tinnitus hearing loss
• Also involve branches of the trigeminal nerve
  dorsal nerve roots
• Tumors are encapsulated, attached to one side of
  the nerve axons do not pass through the tumor
• Consist of
• Antoni -A areas of high cellularity
• Nuclei form palisades Verocay bodies
• Antoni -B myxoid areas

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Schwannoma
Antoni A hyprecellular
Antoni B Sparsely cellular
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• 2. Neurofibromas
• Benign tumors composed predominately of Schwann
  cells, but also containing fibroblasts
  perineural cells
• May involve single or multiple dorsal spinal
  nerve roots (multiple in patients with von
  Ricklinghausen's disease - NF1)
• CN involvement is extremely rare
• May present as
• Localized fusiform enlargement of a nerve or
• Extensively infiltrate along the nerve ? ropy
  enlargement of the nerve its branches
  (plexiform Neurofibroma)
• Plexiform neurofibromas are usually part of NF1,
  excision is very difficult
• Histology
• Wavy spindle shaped cells, myxoid collagenous
  stroma with interspersed nerve fibers

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Acoustic Neurinoma (Schwannoma)
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METASTATIC ICTS

• 50 of ICTs.
• Common Primaries
• Broncho-genic small cell undifferentiated (oat
  cell) ca., Breast ca., Malignant melanoma, RCC.
  Colon ca.
• Sites of metastases
• Cerebral cortex 80
• Rest are in the cerebellum brain stem.
• 50 are multiple at the junction between the
  gray white matter.
• Vertebral column is a common site for metastases
  of
• Breast Prostatic carcinomas
• Thoracic spine 60, Cervical 20 Lumbar 20
• Treatment Radiotherapy

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Metastasis
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• CHOROID PLEXUS PAPILLOMA
• MC in children ? Arising from the lateral
  ventricles
• In adults they are found MC in the 4th ventricle
  
• Present with Hydrocephalus
• Due to either over-production of CSF or to
  obstruction of the ventricular system.
• Consist of papillae with fibrovascular stalks
  covered with a cuboidal or columnar ciliated
  epithelium, recapitulating the structure of the
  normal choroid plexus.

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• COLLOID CYST OF THE THIRD VENTRICLE
• A non-neoplastic cystic lesion
• Morphology
• Having a thin fibrous capsule, a lining of
  Cuboidal to columnar epithelium containing
  gelatinous Proteinaceous material.
• Attached to the roof of the third ventricle at
  the foramina of Munroe may cause sudden
  obstruction of the CSF flow ? acute
  non-communicating hydrocephalus ? brain
  herniation death
• Symptoms headaches (often positional), drop
  attacks, incontinence
• Goblet cells are confirmatory

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MISCELLANEOUS (MIDLINE) TUMORS

• Pinealomas
• True pineocytomas are extremely rare, may also
  have pineoblastomas
• Germinomas
• MC in the pineal suprasellar regions in
  adolescents young adults
• Closely resemble testicular Seminomas ovarian
  Dysgerminomas
• Other GCTs (Teratomas Choriocarcinomas) also
  occur
• Not clear how GCTs arise within the CNS
• Craniopharyngiomas
• Benign cystic tumors of children adolescents
• Develop in the suprasellar region ?
  Hypopituitarism
• Originate from remnants of Rathkes pouch
  contain squamous columnar epithelium,
  calcifications are common.

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CNS LYMPHOMA

• Primary CNS lymphomas
• Account for 1 of ICTs
• MC CNS neoplasm in AIDS other immunosuppressed
  patients often arise deep within the cerebral
  hemispheres are commonly bilateral
• Lymphoma cells exhibit an angiocentric
  distribution
• Usually are B-cell lymphomas many appear to be
  EBV-related.
• Secondary CNS lymphomas
• Lymphomas arising outside of the CNS rarely
  involve the brain parenchyma
• May involve the meninges, intradural spinal nerve
  roots epidural space

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PHAKOMATOSES

• NEUROCUTANEOUS SYNDROMES (PHAKOMATOSES)
• AD
• Hamartomas Neoplasms
• Esp. involving the nervous system skin
• Mutations in tumor suppressor genes
• 1. Neurofibromatosis Type 1 (NF1)
• Neurofibromas, Neurofibro-sarcomas
• Optic nerve Gliomas
• Pigmented cutaneous macules (café au lait spots)
• Pigmented nodules of iris (Lisch nodules)
• 2. Neurofibromatosis Type 2 (NF2)
• Bilateral Schwannomas of CN VIII
• Multiple meningiomas
• Spinal cord Ependymomas

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• 3. Tuberous Sclerosis
• Hamartomas (tubers) in the cerebral cortex,
  Sub-Ependymal hamartomas (candle drippings) ?
  Sub-Ependymal giant cell Astrocytomas
• Seizures mental retardation
• Extra CNS findings
• Kidney (Angiomyolipoma), Heart (Rhabdomyoma MCC
  in kids, adult mixomas ), skin (Angiofibroma)

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Tuberous Sclerosis
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• 4. von Hippel-Lindau disease
• Hemangioblastomas of the cerebellum, retina,
  brain stem spinal cord
• Cysts of liver, kidney pancreas
• ?? incidence of RCC, may be bilateral
• 10 of Hemangioblastomas ? polycythemia

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von Hippel-Lindau disease
Hemangioblastomas