MSK imaging: giant cell tumour: 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: giant cell tumour

Sample item

A 28-year-old has pain near the knee, and the radiograph shows an eccentric, expansile lytic lesion in the epiphysis of the distal femur extending to the subarticular surface, with a soap-bubble appearance and no sclerotic margin. What is the diagnosis?

AOsteosarcomaBEnchondromaCChondroblastomaDGiant cell tumour of bone

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

The answer and the reasoning

D. Giant cell tumour of bone

Giant cell tumour occurs after skeletal maturity, in the epiphysis abutting the subchondral bone, and is eccentric, lytic and well defined without a sclerotic rim. It is locally aggressive and can metastasise to the lung. Chondroblastoma occurs in the epiphysis of skeletally immature patients.

Option by option

A. Osteosarcoma
Osteosarcoma is metaphyseal and sclerotic.
B. Enchondroma
Enchondroma is a central lesion in the small bones of hands.
C. Chondroblastoma
Chondroblastoma occurs in adolescents with open physes and shows calcification.
D. Giant cell tumour of bone (correct)
Correct. An eccentric epiphyseal lytic lesion in an adult is a giant cell tumour.

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 D, Giant cell tumour of bone. Giant cell tumour occurs after skeletal maturity, in the epiphysis abutting the subchondral bone, and is eccentric, lytic and well defined without a sclerotic rim.

Why is "Osteosarcoma" not the answer?

Osteosarcoma is metaphyseal and sclerotic.

Why is "Enchondroma" not the answer?

Enchondroma is a central lesion in the small bones of hands.

Why is "Chondroblastoma" not the answer?

Chondroblastoma occurs in adolescents with open physes and shows calcification.

What concept does this question test?

It tests MSK imaging: giant cell tumour in Radiology. It is locally aggressive and can metastasise to the lung. Chondroblastoma occurs in the epiphysis of skeletally immature patients.

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: giant cell tumour?

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.