MSK imaging: osteosarcoma: 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: osteosarcoma

Sample item

A 15-year-old boy has knee pain and swelling. A radiograph of the distal femur shows a destructive metaphyseal lesion with a sunburst periosteal reaction and Codman triangle. What is the diagnosis?

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

The answer and the reasoning

B. Osteosarcoma

Osteosarcoma is the commonest primary malignant bone tumour in adolescents and typically arises in the metaphysis of long bones around the knee. Sunburst periosteal reaction, Codman triangle and an ossified soft tissue mass are classic. Alkaline phosphatase is often raised.

Option by option

  • A. Simple bone cyst

    A simple bone cyst is a lucent lesion without periosteal reaction.

  • B. Osteosarcoma (correct)

    Correct. Metaphyseal destruction with a sunburst reaction suggests osteosarcoma.

  • C. Osteochondroma

    Osteochondroma is a benign exostosis continuous with the marrow cavity.

  • D. Ewing sarcoma

    Ewing sarcoma occurs in the diaphysis with an onion-skin reaction.

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 B, Osteosarcoma. Osteosarcoma is the commonest primary malignant bone tumour in adolescents and typically arises in the metaphysis of long bones around the knee.

Why is "Simple bone cyst" not the answer?

A simple bone cyst is a lucent lesion without periosteal reaction.

Why is "Osteochondroma" not the answer?

Osteochondroma is a benign exostosis continuous with the marrow cavity.

Why is "Ewing sarcoma" not the answer?

Ewing sarcoma occurs in the diaphysis with an onion-skin reaction.

What concept does this question test?

It tests MSK imaging: osteosarcoma in Radiology. Sunburst periosteal reaction, Codman triangle and an ossified soft tissue mass are classic. Alkaline phosphatase is often raised.

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 MSK imaging: osteosarcoma?

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.