Neuroimaging: colloid cyst: practice question

A Radiology 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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Radiology · Neuroimaging: colloid cyst

Sample item

A young adult has episodic severe headaches worsened by posture and sudden collapse. CT shows a small round hyperdense lesion at the foramen of Monro with dilated lateral ventricles. What is the diagnosis?

AColloid cyst of the third ventricleBMedulloblastomaCPituitary macroadenomaDEpendymoma of the fourth ventricle

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

The answer and the reasoning

A. Colloid cyst of the third ventricle

A colloid cyst sits at the anterosuperior third ventricle, blocks both foramina of Monro, and produces intermittent obstructive hydrocephalus, with a risk of sudden death. It is often hyperdense on CT.

Option by option

A. Colloid cyst of the third ventricle (correct)
Correct. A hyperdense lesion at the foramen of Monro with ventriculomegaly is a colloid cyst.
B. Medulloblastoma
Medulloblastoma is a midline cerebellar tumour of children.
C. Pituitary macroadenoma
A pituitary adenoma lies in the sella.
D. Ependymoma of the fourth ventricle
Ependymoma arises from the floor of the fourth ventricle.

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 Radiology question

What is the answer to this Radiology question?

The best answer is A, Colloid cyst of the third ventricle. A colloid cyst sits at the anterosuperior third ventricle, blocks both foramina of Monro, and produces intermittent obstructive hydrocephalus, with a risk of sudden death.

Why is "Medulloblastoma" not the answer?

Medulloblastoma is a midline cerebellar tumour of children.

Why is "Pituitary macroadenoma" not the answer?

A pituitary adenoma lies in the sella.

Why is "Ependymoma of the fourth ventricle" not the answer?

Ependymoma arises from the floor of the fourth ventricle.

What concept does this question test?

It tests Neuroimaging: colloid cyst in Radiology. It is often hyperdense on CT.

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 Neuroimaging: colloid cyst?

Learn signs with the image, and the disease they point to. Then use the flashcards and the other Radiology 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.