Bone tumours: periosteal osteosarcoma: 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.

Try it

Orthopaedics · Bone tumours: periosteal osteosarcoma

Sample item

A 17-year-old has a painful swelling over the tibial diaphysis. Radiographs show a sunburst reaction arising from the cortical surface, with a cartilaginous matrix on biopsy, and the medullary canal is spared. Which variant of osteosarcoma is this?

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

The answer and the reasoning

D. Periosteal osteosarcoma

Periosteal osteosarcoma is a surface tumour of intermediate grade that arises on the diaphysis of a long bone such as the tibia or femur, and is usually chondroblastic. Parosteal osteosarcoma is low grade and typically sits on the posterior distal femur. Surface variants often spare the medullary cavity and have a better prognosis than conventional disease.

Option by option

  • A. Telangiectatic osteosarcoma

    Telangiectatic osteosarcoma is an intramedullary tumour with blood-filled cystic spaces and lytic destruction.

  • B. Parosteal osteosarcoma

    Parosteal osteosarcoma is a low-grade, densely ossified lesion typically on the posterior distal femur.

  • C. Conventional intramedullary osteosarcoma

    The conventional type arises inside the metaphyseal medullary cavity and destroys the cortex from within.

  • D. Periosteal osteosarcoma (correct)

    Correct. A diaphyseal surface tumour with a chondroblastic matrix and a spared canal is periosteal osteosarcoma.

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 Orthopaedics questions

Questions about this Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is D, Periosteal osteosarcoma. Periosteal osteosarcoma is a surface tumour of intermediate grade that arises on the diaphysis of a long bone such as the tibia or femur, and is usually chondroblastic.

Why is "Telangiectatic osteosarcoma" not the answer?

Telangiectatic osteosarcoma is an intramedullary tumour with blood-filled cystic spaces and lytic destruction.

Why is "Parosteal osteosarcoma" not the answer?

Parosteal osteosarcoma is a low-grade, densely ossified lesion typically on the posterior distal femur.

Why is "Conventional intramedullary osteosarcoma" not the answer?

The conventional type arises inside the metaphyseal medullary cavity and destroys the cortex from within.

What concept does this question test?

It tests Bone tumours: periosteal osteosarcoma in Orthopaedics. Parosteal osteosarcoma is low grade and typically sits on the posterior distal femur. Surface variants often spare the medullary cavity and have a better prognosis than conventional disease.

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: periosteal osteosarcoma?

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.