Head and neck tumours: craniofacial fibrous dysplasia: practice question

A ENT 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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ENT · Head and neck tumours: craniofacial fibrous dysplasia

Sample item

A 14-year-old has progressive painless hard swelling of the maxilla with proptosis. CT shows a ground-glass expansile lesion of the bone. Which mutation is typical?

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

The answer and the reasoning

A. GNAS activating mutation

Fibrous dysplasia replaces normal bone with fibro-osseous tissue due to an activating mutation of GNAS, and CT shows a characteristic ground-glass appearance. In McCune-Albright syndrome it coexists with precocious puberty and cafe-au-lait spots. Surgery is for functional or cosmetic problems and optic nerve compression.

Option by option

  • A. GNAS activating mutation (correct)

    Correct. GNAS mutation is the cause.

  • B. RB1 deletion

    RB1 is the retinoblastoma gene.

  • C. BRCA1 mutation

    BRCA1 is associated with breast and ovarian cancer.

  • D. TP53 deletion

    TP53 mutation causes Li-Fraumeni syndrome.

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 ENT question

What is the answer to this ENT question?

The best answer is A, GNAS activating mutation. Fibrous dysplasia replaces normal bone with fibro-osseous tissue due to an activating mutation of GNAS, and CT shows a characteristic ground-glass appearance.

Why is "RB1 deletion" not the answer?

RB1 is the retinoblastoma gene.

Why is "BRCA1 mutation" not the answer?

BRCA1 is associated with breast and ovarian cancer.

Why is "TP53 deletion" not the answer?

TP53 mutation causes Li-Fraumeni syndrome.

What concept does this question test?

It tests Head and neck tumours: craniofacial fibrous dysplasia in ENT. In McCune-Albright syndrome it coexists with precocious puberty and cafe-au-lait spots. Surgery is for functional or cosmetic problems and optic nerve compression.

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 Head and neck tumours: craniofacial fibrous dysplasia?

Learn tuning fork results and audiogram patterns by sketching them. Then use the flashcards and the other ENT 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.