CNS Pathology case based MCQs-2

CASE : The spinal MRI of a 22-year old male with neurofibromatosis type-2 showed a hyperintense lesion. The lesion was resected and histopathologic section is shown in image.

Question 1: What is the diagnosis?

A. Medulloblastoma
B. Ependymoma
C. Retinoblastoma
D. Central neurocytoma

Question 2: Which of the following statements is true regarding this tumor?

A. They are predominantly supratentorial
B. Posterior fossa tumors in adults have a good prognosis
C. Spinal tumors have a bad prognosis
D. IDH 1 and 2 mutations are present in 100% cases.

Question 3: Identify the variant of the tumor shown in the image below.

A. Tancytic
B. Myxopapillary
C. Subependymoma
D. Anaplastic

Question 4: Which of the following statements is true regarding tancytic ependymoma?

A. GFAP negative
B. Abundant rosettes
C. Can be confused with pilocytic astrocytoma
D. WHO Grade 1

Question 5: Identify the FALSE statement regarding the variant of ependymoma shown below

Image credit- http://www.twitter.com/DrAldehyde

A. WHO Grade 1
B. Arises from filum terminale
C. Aggressive clinical course
D. Mucin stains positive

Question 6: TRUE statement regarding recent molecular classification (WHO CNS 2021 5th edition ) of ependymoma is

A. Spinal ependymomas with MYCN have a good prognosis
B. ZFTA Fusion- favorable prognosis
C. YAP Fusion- poor prognosis
D. Spinal ependymomas with NF 2 mutation- favorable prognosis

ANSWER- Question 1

Correct answer is B- Ependymoma

Ependymomas are characterized by perivascular rosettes and ependymal rosettes which have an empty central lumen

Types of rosettes
ANSWER- Question 2

CORRECT ANSWER IS B

🐱 Majority of of Ependymomas are infratentorial.

🐱Posterior fossa tumors in children have a poor prognosis (PF-A)- associated with loss of H3K27me, whereas Posterior fossa tumors in adults have a god prognosis (PF-B)- H3K27me is retained.

🐱 Spinal ependymomas have a good prognosis, whereas a small number of ependymomas associated with MYCN have a poor outcome.

🐱IDH 1 and 2 are associated with astroctyomas and oligodendroglomas but nor ependymomas.

ANSWER-Question 3

CORRECT ANSWER IS A

Diagnosis is TANCYTIC EPENDYMOMA, 🐱 Tancytes are cells with fibrillary processes which line ventricles along with ependymal cells.

Types of tancytes
ANSWER – Question 4

Correct They are GFAP positive 🐱Confused with pilocytic astrocytoma because of the prominent fibrillary projections 🐱It is a GRADE II Ependymoma 🐱 Ependymal rosettes and pseudorosettes are scanty in tanytic ependymoma, which makes diagnosis challenging.

ANSWER- Question 5

Correct answer is C
💀Diagnosis is myxopapillary ependymoma
💀It is a Grade II Tumor according to latest WHO
💀It is common in adults and arises from the filum terminale
💀It is clinically indolent ( nor aggressive)
💀Stains for Mucin is positive.

Mucin stains positive in myxopapillary ependymoma
ANSWER – Question 6

Correct answer is D

Spinal ependymomas with NF2 mutation has a good prognosis

Summary of latest molecular updates in ependymoma

CENTRAL CHROMATOLYSIS

Central chromatolysis is a condition seen in neurons with axonal reaction.

Lets look at the details now.

  1. Axonal reaction is a change observed in the cell body during regeneration of the axon; it is best seen in anterior horn cells of the spinal cord when motor axons are cut or seriously damaged.
  2. The increase in protein synthesis that occurs in response to the injury is reflected in enlargement and rounding up of the cell body, peripheral displacement of the nucleus, enlargement of the nucleolus, and dispersion of Nissl substance from the center to the periphery of the cell (central chromatolysis).

Below is a pictorial difference between normal neurons and neurons with axonal reaction.

REVIEW QUESTIONS

1. Axonal reaction is visible in which of the which of the following regions of the central nervous system?

A. Posterior horn cells of the spinal cord

B. Anterior horn cells of the spinal cord

C. Cerebral cortex

D. Cerebellum

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Answer is B: Axonal reaction is a change observed in the cell body during regeneration of the axon; it is best seen in anterior horn cells of the spinal cord when motor axons are cut or seriously damaged

2. Dispersion of nissil substance to the periphery of a neuron is characteristic of which of the following?

A. Axonal reaction

B. Wallerian degeneration

C. Neuronal degeneration

D. Red neurons.

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Answer is A:

The process described in the question is central chromatolysis and is associated with axonal reaction.

Central nervous system (CNS) tumors pathology mcq pdf with answers

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RECENT BLOGS

5 ways to differentiate Lewy body and Pick body in a brain biopsy or during autopsy

Degenerative brain diseases are seldom biopsied. They are diagnosed predominantly during autopsies. Lewy body and Pick body are particularly difficult to distinguish.

Lewy bodies:  They are seen in Parkinson’s disease as well as dementia with lewy bodies. Cortical lewy bodies are characteristic of dementia with lewy bodies whereas lewy bodies in the basal ganglia are seen in Parkinson’s disease.

Pick bodies:  They are seen fronto-temporal dementia.  As the name suggests,  they can be seen in frontal and temporal areas.

Here are 5 ways to differentiate lewy body and pick body based on light microscopy,  immunohistochemistry and electron microscopy.

1. STAINING

Pick bodies are slightly more basophilic compared to Lewy body.

PICK BODY – WITH SLIGHTLY BASOPHILIC APPEARANCE
LEWY BODY WITH EOSINOPHILIC APPEARANCE

2. PRESENCE OR ABSENCE OF A CENTRAL DOT

Lewy body has an eosinophilic central dot, as in the above picture which pick body lacks.

3. PRESENCE OR ABSENCE OF A PERIPHERAL HALO

Lewy body has a peripheral halo wheras Pick body doesn’t

PERIPHERAL HALO IN LEWY BODY

4. IMMUNOHISTOCHEMICAL STAINS

Lewy body stains positive with anti-alpha synuclein antibodies. Pick body stains positive with anti-tau antibodies.

5. ELECTRON MICROSCOPY

On electron microscopy Lewy body is composed of fuzzy deposits on filaments that radiated from a central core. Pick body is composed of random filaments of smooth contour.

Electron microscopy findings of Lewy body
Electron microscopic findings of Pick body

That’s all the ways to differentiate PICK BODY AND LEWY BODY

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If you are interested in illustrations click below

5 ways to differentiate gliosis and glioma.

Gliosis is often confusing and challenging to differentiate from glioma. Adding to the trouble, is the fact that gliomas often accompany gliosis. Therefore it is essential to differentiate gliosis and gliomas.

5 ways to differentiate gliosis and glioma

Gliosis is also seen in demyelinaying diseases and infections

Ideally ‘gliosis with glioma’ and ‘gliosis without glioma’ shoud be differentiated, but to keep things simple let’s look at a few clues to tell the two apart.

GLIOMAS Vs GLIOSIS

1. MITOSIS

Mitosis naturally is characteristic of multiplying cells. Hence mitosis is lower in gliosis when compared to glioma. As a general rule the Ki67 proliferation index does not exceed > 5% in gliosis.

This isn’t entirely useful, because low grade gliomas do not show mitosis. Ki-67 stains may be useful to quantify mitosis by immunohistochemistry.

2. MARGINS

This is probably the most important differentiating fearure.

GLIOMAS- EXPAND

GLIOSIS- CONTRACTS

However important this finding is, it is difficult to confirm without serial radiographs.

3. CELLULAR DENSITY

Gliosis- cellular density is even

Glioma- cellular density is uneven

4. NUCLEUS

Gliosis- nuclei of cells don’t touch each other.

Glioma- nuclei of cells often touch each other.

5. IMMUNOHISTOCHEMICAL MARKERS

Gliosis- negative for markers such as IDH and p53.

Glioma- positive for markers such as IDH and p53.

IDH and p53 are not positive in many gliomas but, when they are positive they can be diagnostic.

In this context it would be fitting to discuss quickly about a condition which often mimicks brain tumor- GLIOMATOSIS CEREBRI

Gliomatosis cerebri is a rare primary brain tumor. It is commonly characterized by diffuse infiltration of the brain with neoplastic glial cells that affect various areas of the cerebral lobes. Gliomatosis cerebri behaves like a malignant tumor that is very similar to Glioblastoma.

Though it is not an easy task to differentiate gliomas and gliomas, hope these tips would be of some use.

Thank you!

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