Bone tumours: chondromyxoid fibroma: 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: chondromyxoid fibroma

Sample item

A 20-year-old has a mild ache in the knee. Radiographs show an eccentric, lobulated lytic lesion with a scalloped sclerotic margin in the metaphysis of the proximal tibia. Biopsy shows lobules of myxoid and chondroid tissue. What is the diagnosis and the usual treatment?

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

The answer and the reasoning

A. Chondromyxoid fibroma; curettage with bone grafting

Chondromyxoid fibroma is a rare benign cartilage-forming tumour that occurs in the metaphysis of long bones, most often the proximal tibia, in the second and third decades. It is eccentric and lytic with a sharply defined scalloped sclerotic margin. Curettage with bone grafting is the treatment, and local recurrence is not uncommon.

Option by option

  • A. Chondromyxoid fibroma; curettage with bone grafting (correct)

    Correct. An eccentric metaphyseal lesion with a scalloped margin and myxoid lobules is chondromyxoid fibroma.

  • B. Enchondroma; steroid injection

    An enchondroma is a central medullary lesion with calcifications, not an eccentric lesion.

  • C. Osteosarcoma; amputation only

    Osteosarcoma is a malignant tumour with a permeative pattern and a periosteal reaction.

  • D. Simple bone cyst; observation always

    A simple bone cyst is a central lesion without a scalloped sclerotic margin.

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, Chondromyxoid fibroma; curettage with bone grafting. Chondromyxoid fibroma is a rare benign cartilage-forming tumour that occurs in the metaphysis of long bones, most often the proximal tibia, in the second and third decades.

Why is "Enchondroma; steroid injection" not the answer?

An enchondroma is a central medullary lesion with calcifications, not an eccentric lesion.

Why is "Osteosarcoma; amputation only" not the answer?

Osteosarcoma is a malignant tumour with a permeative pattern and a periosteal reaction.

Why is "Simple bone cyst; observation always" not the answer?

A simple bone cyst is a central lesion without a scalloped sclerotic margin.

What concept does this question test?

It tests Bone tumours: chondromyxoid fibroma in Orthopaedics. It is eccentric and lytic with a sharply defined scalloped sclerotic margin. Curettage with bone grafting is the treatment, and local recurrence is not uncommon.

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: chondromyxoid fibroma?

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.