Bone tumours: enchondroma versus chondrosarcoma: practice question

A Orthopaedics 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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Orthopaedics · Bone tumours: enchondroma versus chondrosarcoma

Sample item

A 48-year-old with a known enchondroma of the femur develops new persistent pain without any fracture. Imaging shows endosteal scalloping of more than two thirds of the cortical thickness. What does this suggest?

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

The answer and the reasoning

A. Malignant transformation to chondrosarcoma

Enchondromas in long bones are usually painless unless fractured, so new pain without a fracture is worrying. Deep endosteal scalloping, cortical destruction and growth after maturity suggest low-grade chondrosarcoma. Biopsy and wide excision are then considered.

Option by option

  • A. Malignant transformation to chondrosarcoma (correct)

    Correct. New pain with deep endosteal scalloping suggests chondrosarcoma.

  • B. Bone infarct

    A bone infarct has a serpiginous sclerotic border and does not scallop the cortex.

  • C. Osteoid osteoma

    Osteoid osteoma has a small nidus and night pain relieved by aspirin.

  • D. Simple degeneration of the enchondroma

    Benign enchondromas do not typically cause new pain.

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.

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Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is A, Malignant transformation to chondrosarcoma. Enchondromas in long bones are usually painless unless fractured, so new pain without a fracture is worrying.

Why is "Bone infarct" not the answer?

A bone infarct has a serpiginous sclerotic border and does not scallop the cortex.

Why is "Osteoid osteoma" not the answer?

Osteoid osteoma has a small nidus and night pain relieved by aspirin.

Why is "Simple degeneration of the enchondroma" not the answer?

Benign enchondromas do not typically cause new pain.

What concept does this question test?

It tests Bone tumours: enchondroma versus chondrosarcoma in Orthopaedics. Deep endosteal scalloping, cortical destruction and growth after maturity suggest low-grade chondrosarcoma. Biopsy and wide excision are then considered.

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 Bone tumours: enchondroma versus chondrosarcoma?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.