CNS tumours: pilocytic astrocytoma: practice question

A Pathology question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Pathology · CNS tumours: pilocytic astrocytoma

Sample item

A 7-year-old child has headache, vomiting and ataxia. MRI shows a cystic cerebellar mass with an enhancing mural nodule. Histology shows bipolar cells with eosinophilic corkscrew-shaped cytoplasmic inclusions. What is the best diagnosis?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

A. Pilocytic astrocytoma (WHO grade 1)

Pilocytic astrocytoma is a slow-growing tumour of childhood with a biphasic pattern of compact bipolar cells and loose microcystic areas, plus Rosenthal fibres and eosinophilic granular bodies. It is usually cured by resection and often carries a BRAF fusion. Medulloblastoma is a small blue cell tumour of the vermis.

Option by option

  • A. Pilocytic astrocytoma (WHO grade 1) (correct)

    Correct. Cystic cerebellar tumour with Rosenthal fibres indicates pilocytic astrocytoma.

  • B. Glioblastoma

    Glioblastoma shows pseudopalisading necrosis and occurs mainly in adults.

  • C. Ependymoma

    Ependymoma shows perivascular pseudorosettes and arises in the fourth ventricle.

  • D. Medulloblastoma

    Medulloblastoma consists of small round blue cells and Homer Wright rosettes.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

More Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is A, Pilocytic astrocytoma (WHO grade 1). Pilocytic astrocytoma is a slow-growing tumour of childhood with a biphasic pattern of compact bipolar cells and loose microcystic areas, plus Rosenthal fibres and eosinophilic granular bodies.

Why is "Glioblastoma" not the answer?

Glioblastoma shows pseudopalisading necrosis and occurs mainly in adults.

Why is "Ependymoma" not the answer?

Ependymoma shows perivascular pseudorosettes and arises in the fourth ventricle.

Why is "Medulloblastoma" not the answer?

Medulloblastoma consists of small round blue cells and Homer Wright rosettes.

What concept does this question test?

It tests CNS tumours: pilocytic astrocytoma in Pathology. It is usually cured by resection and often carries a BRAF fusion. Medulloblastoma is a small blue cell tumour of the vermis.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study CNS tumours: pilocytic astrocytoma?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.