Neurosurgical radiology quiz. A case of oligodendroglioma.

1. RADIOLOGY QUIZ
DR. FARRUKH JAVEED

2. • 36 years old male shopkeeper presents
with Sudden loss of
consciousness.
• Hx of multiple episodes of seizures in
last 2 years, previous episode was 3
months back.
• No hx of headache or any other
neurological deficit. No previous hx of
head trauma.

3. Hounsfield Units On CT Scan

4. DIFFERENTIALS
• Oligodendroglioma
• AV Malformation
• Astrocytoma
• Calcified Tuberculoma
• Atypical Meningioma

5. OLIGODENDROGLIOMA
• 2-4 % of primary brain tumors
• Male:Female 3:2
• Average age 40 years
• Usual presentation is seizures for many years prior to the diagnosis.
• Seizures are the presenting symptoms in 50-80% of cases.
• Frontal lobe is the commonest location.
• Calcifications:
– 28-60% on plain radiographs
– 90% on CT scans.

6. WHO CLASSIFICATION: GLIOMA

7. PATHOLOGY
• Usually solid tumors
• 16% have the cystic component.
• "fried egg" appearance under the light microscope due to perinuclear halos.
• 33-41% have some component of ependymal or neoplastic astrocytic cells
(oligoastrocytomas or mixed gliomas).
• Grading:
– Low grade (WHO grade II): Oligodendroglioma
– High grade (WHO grade III): Anaplastic oligodendroglioma

8. SMITH GRADING
1. Nuclear/Cytoplasmic Ratio
2. Maximal Cell Density
3. Pleomorphism
4. Endothelial Proliferation
5. Necrosis
• Grade A: 94 months
• Grade B: 51 months
• Grade C: 45 months
• Grade D: 17 months

9. CT SCAN
• Plain CT Scan: Mixed density
(hypodense to isodense). Calcifications
90%
• Contrast CT: 50% of
oligodendrogliomas enhance.

10. MRI T1WI: Hypointense

11. MRI T2WI: Hyperintense (except
calcified areas)

12. FLAIR: Hyperintense

13. T1 + CONTRAST: Heterogeneous

14. MRI
• T1: hypointense
• T2: hyperintense (except calcified
areas)
• T1 Contrast (Gd): contrast
enhancement is common usually
heterogeneous when present but it is
not a reliable indicator of tumor grade.

15. TREATMENT
• Chemotherapy:
– PCV [Procarbazine, CCNU (Lomustine) and Vincristine]
– Most ODGs respond to chemotherapy in less than 3 months often with a reduction
in size.
– Chromosome 1p & 19q loss shows good response to chemo and better prognosis.
• Surgery:
– ODGs with significant mass effect
– Resectable low grade ODGs
– High grade ODGs

16. PROGNOSIS
• Better Prognosis:
– Pure ODGs
– Calcified ODGs
– Frontal lobe ODGs
– Chromosomal 1p and 19q loss

17. THANK YOU….