Respiratory medicine: malignant pleural mesothelioma immunohistochemistry: practice question

A General Medicine 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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General Medicine · Respiratory medicine: malignant pleural mesothelioma immunohistochemistry

Sample item

A 62-year-old retired shipyard worker has progressive chest pain and breathlessness. CT shows nodular pleural thickening with a right effusion, and a pleural biopsy shows epithelioid malignant cells. Which immunohistochemical profile favours mesothelioma over lung adenocarcinoma?

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

The answer and the reasoning

D. Calretinin positive and TTF-1 negative

Mesothelioma cells stain for calretinin, WT1 and cytokeratin 5/6, and are negative for the adenocarcinoma markers TTF-1, napsin A and CEA. Because morphology alone can be misleading, a panel of markers is needed to separate them.

Option by option

  • A. TTF-1 positive and calretinin negative

    This profile is the reverse and indicates lung adenocarcinoma.

  • B. Napsin A positive and CK5/6 negative

    Napsin A positivity with negative CK5/6 also favours adenocarcinoma.

  • C. CEA positive and calretinin negative

    CEA positivity points to adenocarcinoma, with negative calretinin.

  • D. Calretinin positive and TTF-1 negative (correct)

    Correct. Positive mesothelial markers with negative adenocarcinoma markers define mesothelioma.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is D, Calretinin positive and TTF-1 negative. Mesothelioma cells stain for calretinin, WT1 and cytokeratin 5/6, and are negative for the adenocarcinoma markers TTF-1, napsin A and CEA.

Why is "TTF-1 positive and calretinin negative" not the answer?

This profile is the reverse and indicates lung adenocarcinoma.

Why is "Napsin A positive and CK5/6 negative" not the answer?

Napsin A positivity with negative CK5/6 also favours adenocarcinoma.

Why is "CEA positive and calretinin negative" not the answer?

CEA positivity points to adenocarcinoma, with negative calretinin.

What concept does this question test?

It tests Respiratory medicine: malignant pleural mesothelioma immunohistochemistry in General Medicine. Because morphology alone can be misleading, a panel of markers is needed to separate them.

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 Respiratory medicine: malignant pleural mesothelioma immunohistochemistry?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.