Endocrine: papillary thyroid carcinoma: practice question

A Pathology 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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Pathology · Endocrine: papillary thyroid carcinoma

Sample item

A 30-year-old woman has a firm thyroid nodule with cervical lymph node metastasis. Histology shows papillae with optically clear nuclei and nuclear grooves. Which genetic alteration is most common in sporadic cases of this tumour?

AInactivating TP53 mutationBPoint mutation of the RET geneCBRAF V600E mutationDRAS mutation with PAX8-PPAR gamma fusion

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

The answer and the reasoning

C. BRAF V600E mutation

BRAF V600E is the most frequent genetic event in sporadic papillary thyroid carcinoma, followed by RET/PTC rearrangements in radiation-related cases. The tumour spreads through lymphatics to cervical nodes and still has an excellent prognosis. RAS and PAX8-PPAR gamma occur in follicular neoplasms.

Option by option

A. Inactivating TP53 mutation
TP53 inactivation is typical of anaplastic carcinoma.
B. Point mutation of the RET gene
RET point mutations cause medullary thyroid carcinoma in MEN 2.
C. BRAF V600E mutation (correct)
Correct. BRAF V600E is the commonest alteration in papillary carcinoma.
D. RAS mutation with PAX8-PPAR gamma fusion
RAS mutation and PAX8-PPAR gamma fusion characterise follicular neoplasms.

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 Pathology question

What is the answer to this Pathology question?

The best answer is C, BRAF V600E mutation. BRAF V600E is the most frequent genetic event in sporadic papillary thyroid carcinoma, followed by RET/PTC rearrangements in radiation-related cases.

Why is "Inactivating TP53 mutation" not the answer?

TP53 inactivation is typical of anaplastic carcinoma.

Why is "Point mutation of the RET gene" not the answer?

RET point mutations cause medullary thyroid carcinoma in MEN 2.

Why is "RAS mutation with PAX8-PPAR gamma fusion" not the answer?

RAS mutation and PAX8-PPAR gamma fusion characterise follicular neoplasms.

What concept does this question test?

It tests Endocrine: papillary thyroid carcinoma in Pathology. The tumour spreads through lymphatics to cervical nodes and still has an excellent prognosis. RAS and PAX8-PPAR gamma occur in follicular neoplasms.

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 Endocrine: papillary thyroid carcinoma?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.