The document discusses various types of central nervous system (CNS) tumors. It notes that CNS tumors comprise 10% of all tumors and are most common in children and the fifth decade of life. Primary CNS tumors are infiltrative while metastases are well-demarcated. Common primary tumor types include meningiomas, gliomas such as astrocytomas and oligodendrogliomas, and nerve sheath tumors like schwannomas. Clinical features can include increased intracranial pressure, neurological deficits, and seizures. Microscopic features help distinguish tumor types, such as psammoma bodies in meningiomas and pseudopalisades in glioblastomas.

1. Pathology of
CNS Tumors

2. CNS Tumors
 Limited space, filled by Delicate vital structure..
 Normal brain is semifluid in consistency….!
 Highly sensitive to hypoxia, Critical blood supply
 Increased pressure – destructive.
 Location determines nature than the tumor
itself.
 Common site of metastasis.
General Considerations

3. CNS Tumors
General Considerations
 Comprise: 10% of all tumors
 Most common childhood neoplasms
 Peak incidence at 5th decade
 Supratentorial tumors in adults
 Infratentorial tumors in childhood
 Primary tumors  infiltrative
 Metastasis  well-demarcated
 Intraneural spread, no extraneural spread

4. CNS Tumors
Simple Classification:
1. Primary Tumors:
 Mainly from supporting glia, nerve
sheath, primitive cells, blood
vessel/bone.
2. Secondary Tumors - metastasis from
Ca breast, lung, GIT etc.* Commonest.
“Mature Neurons do not give rise to neoplasms.”
(Permanent cells)

5. CNS Tumors
Primary brain tumors.
 Meninges: meningioma
 Glia -
 Astrocytes - astrocytoma
 Oligodendrocytes - oligodendroglioma
 Ependyma – ependymoma, choroid plexus
papilloma, colloid cyst (Ventricles).
 Primitive cells: “blastoma” e.g. neuroblastoma.
 Neuronal * : ganglioglioma, gangliocytoma
 Nerve sheath: schwannoma, neurofibroma
 Pituitary: adenoma, craniopharyngioma
 Vascular & Bone tumors:

6. CNS Tumors
Clinical features:
 Raised Intracranial Pressure.
 Headache, vomiting, slow pulse,
papilledema.
 Local damage:
 Nerve & tract deficits, Paralysis,
seizures etc.

7. CNS Tumors
Meningioma:
 Arise from arachnoid granulations of
venous sinuses. Attached to dura.
 Common sites: parasagittal (falx), sphenoid
ridge, olfactory groove
 Females common (2:1)
 Well demarcated – Compression - No Invasion
 Microscopic: whorls and psammoma bodies
 Hyperostosis over the tumor.
 Slow growth, well differentiated, no spread
(Benign).

9. Meningioma

10. CNS Tumors
Meningioma

11. CNS Tumors
Meningioma

12. CNS Tumors
Meningioma

13. CNS Tumors
Meningioma

14. Psammoma bodies

15. CNS Tumors
Glioma:
 Gliomas are neoplasms of glial cells.
 Astrocytoma – Commonest benign
tumors with malignant behavior.
 Ependymoma – Rare, 4th ventricle.
 Oligodendroglioma – Benign, adults,
rare.

16. CNS Tumors
Astrocytoma
 Astrocytoma – Commonest tumors of
adults. (80%)
 Well differentiated, slow growing.
 Benign - but malignant behavior.
 Infiltrative, poor demarcation
 Glioblastoma Multiforme -
Malignant form of Astrocytoma.

17. CNS Tumors
Astrocytomas
Adults:
 Supratentorial (Cerebrum),
 Solid, Malignant, Fibrillary
Children:
 Infratentorial (Cerebellum),
 Cystic, Benign, Pilocytic

18. CNS Tumors
Fibrillary astrocytomas
 Grossly solid
 Common in cerebral hemispheres
 Low grade in young, higher grade in
older
 Grading
 astrocytoma (low grade)
 Anaplastic astocytoma
 glioblastoma multiforme (high grade)

19. Astrocytoma - fibrillary

20. CNS Tumors Fibrillary astrocytoma:
microscopic
 Low grade- hypercellularity, pleomorphism
 Anaplastic- as above plus mitosis, vascular
endothelial proliferation
 Glioblastoma multiforme- as above plus
necrosis and pseudopalisades. Grossly
variegated appearance (multiforme)

21. Glioblastoma – high grade Astrocytoma

22. Glioma Brain Stem

23. CNS Tumors
Glioma Cerebrum

24. Glioma:

25. Fibrillary Astrocytoma (Glioma)

26. Glioblastoma Multiforme

27. Glioblastoma Cerebrum

28. Glioma:

29. Glioma

30. Astrocytoma

31. Glioblastoma Multiforme

32. Glioblastoma Multiforme

33. CNS Tumors
Pilocytic astrocytoma
 Common in childhood
 Most slow growing of the gliomas
 Sites: cerebellum, around III V., optic nerve
 Grossly cystic with mural nodule
 Microscopic
 elongated hair-like (pilo) elongated cells
 Rosenthal fibers

34. Pilocytic Astrocytoma - children

35. Pilocytic astrocytoma
Mural nodule

37. Other CNS tumors

38. CNS Tumors
Neuroectodermal Tumors
 Origin from primitive blast cells.
 Rosettes - attempted nerve formation.
1. Medulloblastoma – Cerebellum
2. Retinoblastoma - Retina
3. Neuroblastoma – Adrenal glands
4. Ganglioneuroma - Mediastinum

39. Medulloblastoma

40. Medulloblastoma

41. Ependymoma Cerebellum

42. Ependymoma-hemorrhage

43. Ependymoma

44. CNS Tumors
Brain Metastasis -
(lung)

45. CNS Tumors
Metastatic tumors

46. CNS Tumors
Brain Metastasis

48. Peripheral Nerve
(Sheath) Tumors
Neurofibroma
Schwannoma

49. CNS Tumors
Nerve Sheath Tumors:
 Neurofibroma:
 Epi & endoneurial fibroblasts.
 Form whorls of fibroblasts
 Well differentiated, benign,
 Two types:
 Classic form - Cutaneous / nerve - Solitary
collagen matrix, spindle cells,
 Plexiform - Multiple, infiltrative, myxoid.

50. CNS Tumors
Nerve Sheath Tumors:
 Schwannoma:
 Schwann cells, form whorls
 Nuclear palisading
 Antoni A & B pattern.
 Verocay bodies.

51. CNS Tumors
Schwannoma

52. CNS Tumors
Neurilemmoma

53. CNS Tumors
Schwannoma/Acoustic neuroma

54. CNS Tumors
Schwannoma:

55. CNS Tumors
Antoni A - Antoni B

56. CNS Tumors
Antony A
Antoni B
Palisades

57. CNS Tumors
Schwannoma Cerebellum

58. CNS Tumors
Neurofibromatosis:
 Type I (common):(AD, 17q, 1:3000)
 Plexiform & solitary neurofibromas
 Optic nerve gliomas, Lisch nodules, Café au lait
spots.
 Type II (rare):(22q, 1:40,000)
 Bilateral acoustic schwannoma/osis
 Multiple meningioma/osis, ependymoma of
spinal cord

59. CNS Tumors
Phakomatosis (Neurocut. dysplasia)
• Neurologic abnormalities + defects of skin or
retina (ectodermal).
• Neurofibromatosis (von Recklinghausen)
• Tuberous Sclerosis
• Sturge-Weber Sy (Encephalofacial
Angiomatosis)
• von Hippel-Lindau Disease
• Neurocutaneous Melanosis

60. CNS Tumors
Neurofibromatosis - Von Recklinghausen
Dominant inheritance
Multiple neurofibromas
 Central - CNS
 peripheral nerves
Increased incidence of:
 meningioma
 glioma
 schwannoma - bilateral VIII N.
Cafe-au-lait (melanosis) in skin
Elephantiasis: increased connective
tissue

61. CNS Tumors
Von Recklinghausen Disease:

62. CNS Tumors
Multiple neurofibromas
Café-au-lait spots
Von Recklinghausen’s
Disease

63. CNS Tumors
Von Recklinghausen Disease:

64. CNS Tumors
Café-au-lait spots

65. CNS Tumors
Plexiform Neurofibroma:

66. CNS Tumors
Tuberous Sclerosis
1. Dominant inheritance
2. Clinical triad:
seizures
mental retardation
adenoma sebaceum
3. Retinal hamartoma (phakoma)
4. Tubers in cerebral cortex
5. Subependymal giant cell astrocytoma
6. Hamartomas in other organs: heart, kidney

67. CNS Tumors
Adenoma sebaceum

68. CNS Tumors
Neurofibromatosis Type II:
Bil Schwannomas
Meningiomas
Gliomas
Pheochromocytomas

69. CNS Tumors
Acoustic
Schwannoma

70. CNS Tumors
Plexiform Neurofibroma:

71. CNS Tumors
Malignant Neurofibroma:

72. CNS Tumors
Peripheral nerve tumors
Schwannoma
 Schwann cells
 Compress the nerve
trunk
 Encapsulated
 Easily resectable without
nerve damage
 Microscopic:
 Antony A and B fibers
 Verocay bodies
Neurofibroma
 Schwann cells, neurites,
fibroblasts
 Fusiform and involves
nerve trunk
 Not encapsulated
 Not resectable without
sacrificing nerve
 Micro- Intermingled cells
with wavy nuclei

73. CNS Tumors
Brain Tumors: Microscopic
Tumor Microscopic
Meningioma Whorls and psammoma
bodies
Glioblastoma Pseudopalisades
Oligodendroglioma Mosaic/poached-egg
Ependymoma Perivascular pseudorosettes
Medulloblastoma Rosettes (Homer-Wright)