MSK imaging: aneurysmal bone 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 · MSK imaging: aneurysmal bone cyst

Sample item

A 14-year-old has pain and swelling at the distal femur. Radiograph shows an eccentric, expansile, lytic lesion with a thin shell, and MRI shows multiple fluid-fluid levels. What is the diagnosis?

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

The answer and the reasoning

C. Aneurysmal bone cyst

Aneurysmal bone cysts are blood-filled cavities that expand the bone, and the fluid-fluid levels on MRI or CT result from layering of blood products. Telangiectatic osteosarcoma can mimic it and needs exclusion.

Option by option

  • A. Osteochondroma

    An osteochondroma is a bony outgrowth continuous with the cortex.

  • B. Simple bone cyst

    A simple cyst is central with a single cavity.

  • C. Aneurysmal bone cyst (correct)

    Correct. An expansile lesion with multiple fluid-fluid levels is an aneurysmal bone cyst.

  • D. Osteosarcoma

    Osteosarcoma shows aggressive periosteal reaction and a soft tissue mass.

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 Radiology questions

Questions about this Radiology question

What is the answer to this Radiology question?

The best answer is C, Aneurysmal bone cyst. Aneurysmal bone cysts are blood-filled cavities that expand the bone, and the fluid-fluid levels on MRI or CT result from layering of blood products.

Why is "Osteochondroma" not the answer?

An osteochondroma is a bony outgrowth continuous with the cortex.

Why is "Simple bone cyst" not the answer?

A simple cyst is central with a single cavity.

Why is "Osteosarcoma" not the answer?

Osteosarcoma shows aggressive periosteal reaction and a soft tissue mass.

What concept does this question test?

It tests MSK imaging: aneurysmal bone cyst in Radiology. Telangiectatic osteosarcoma can mimic it and needs exclusion.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 MSK imaging: aneurysmal bone 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.