CNS: medulloblastoma: 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: medulloblastoma

Sample item

A 5-year-old child has morning vomiting, unsteady gait and papilloedema. MRI shows a midline cerebellar vermis mass with hydrocephalus. Biopsy shows sheets of small blue cells forming Homer Wright rosettes. What is the most characteristic route of metastasis?

AHaematogenous spread to the lungsBLymphatic spread to cervical nodesCSeeding through the cerebrospinal fluidDDirect spread through the foramen magnum into the neck muscles

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

The answer and the reasoning

C. Seeding through the cerebrospinal fluid

Medulloblastoma is a highly cellular embryonal tumour of the cerebellum in children, belonging to the primitive neuroectodermal group. It obstructs the fourth ventricle, causing raised intracranial pressure, and commonly spreads through the CSF to the spinal cord and meninges as drop metastases. It is radiosensitive, so treatment uses surgery with craniospinal irradiation and chemotherapy.

Option by option

A. Haematogenous spread to the lungs
Extraneural haematogenous spread is uncommon in central nervous system tumours.
B. Lymphatic spread to cervical nodes
The brain has no conventional lymphatics, so cervical node spread is rare.
C. Seeding through the cerebrospinal fluid (correct)
Correct. CSF dissemination to the leptomeninges and spine is typical of medulloblastoma.
D. Direct spread through the foramen magnum into the neck muscles
Direct neck invasion is not the characteristic route of dissemination.

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.

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, Seeding through the cerebrospinal fluid. Medulloblastoma is a highly cellular embryonal tumour of the cerebellum in children, belonging to the primitive neuroectodermal group.

Why is "Haematogenous spread to the lungs" not the answer?

Extraneural haematogenous spread is uncommon in central nervous system tumours.

Why is "Lymphatic spread to cervical nodes" not the answer?

The brain has no conventional lymphatics, so cervical node spread is rare.

Why is "Direct spread through the foramen magnum into the neck muscles" not the answer?

Direct neck invasion is not the characteristic route of dissemination.

What concept does this question test?

It tests CNS: medulloblastoma in Pathology. It obstructs the fourth ventricle, causing raised intracranial pressure, and commonly spreads through the CSF to the spinal cord and meninges as drop metastases. It is radiosensitive, so treatment uses surgery with craniospinal irradiation and chemotherapy.

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: medulloblastoma?

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.