Find a summary of molecular alterations in ependymoma

SOME MCQs RELATED TO THE SUMMARY

1. Shown in the image is an L1CAM immunostain in an ependymoma. Which of the following is true about this entity?

1. The histologic features correspond to anaplastic ependymoma, WHO grade III
2. The immunohistochemical stain is confirmed by FISH
3. This immunophenotype is characteristic of posterior fossa ependymomas
4. This immunophenotype may not  be seen in central neurocytoma, anaplastic astrocytoma and primitive neuronal tumors

Answer to Question 1

B. The immunohistochemical stain is confirmed by FISH- IHC positivity is often confirmed using FISH

Cytoplasmic immunopositivity for L1CAM is characteristic of supratentorial – ZFTA fusion ependymomas.

Option A: ZFTA-fused supratentorial ependymomas show varying ependymoma AND degrees of anaplasia and have been regarded as CNS WHO grade 2 or 3 on this basis.

Option C: ZFTA- fused ependymomas are often supratentorial and not posterior fossa

Option D:  L1CAM Positivity id also seen in 

• Olfactory neuroblastoma
• Central neurocytoma
• Gangliocytoma
• Primitive neuronal tumors

Reference : WHO CNS Tumors 5th edition page no 165

Question 2

Which of the following combinations of ependymoma molecular subtype and clinical characteristics is correct?

1. Posterior fossa ependymoma, subtype A / supratentorial / poor
2. Spinal myxopapillary ependymoma / supratentorial / good
3. Supratentorial ependymoma, RELA / children / poor
4. Supratentorial ependymoma, YAP1 / adults / good

Answer to question 2

C. Supratentorial ependymoma, RELA / children / poor

RELA fusion ependymomas are now classified under ZFTA fusion under latest WHO 5th edition 

Molecular subtype of ependymoma	Site	Age	Prognosis
ZFTA fusion	Supratentorial	Both children and adults	Poor
YAP 1 fusion	Supratentorial	Both children and adults	Good
Posterior fossa A	Posterior fossa	Predominantly children	Poor
Posterior fossa B	Posterior fossa	Predominantly children	Good
Spinal 1	NF-1	Adults	Good
Spinal 2	NMYC	Adults	Good

Reference : WHO CNS Tumors 5th edition page no 159