Pictorial lesson in CNS Tumours

1. Pictorial lesson in CNS Tumours Dr H.K.Lord

2. Anatomy Reminder

3. Malignant Brain Tumours

4. Glioma – Grading of Tumours

5. 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.

6. 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.

7. 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.

8. Diffuse, low-grade astrocytoma • In the white matter, there is a subtle infiltration of astrocytes with only slightly irregular features.

9. 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

10. 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

11. 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.

12. 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.

13. 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.

14. Benign CNS Tumours

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

16. 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.

17. 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 Rathke’s pouch

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

19. Secondary CNS Tumours

20. 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

21. 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.

22. 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.

23. Childhood CNS Tumours

24. 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.

25. 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.

26. 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.

27. 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

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

29. 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/