Haemodynamics: thrombosis: 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 · Haemodynamics: thrombosis

Sample item

At autopsy a large vessel contains a dark red mass that is gelatinous, smooth, shiny and not adherent to the wall. A second mass is dry and friable, and adherent, with alternating pale and dark layers. What does the second mass indicate?

AA postmortem clotBAn embolus from a distant site onlyCAn antemortem thrombus with lines of ZahnDA fibrin cast formed after death

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

The answer and the reasoning

C. An antemortem thrombus with lines of Zahn

Lines of Zahn are alternating pale layers of platelets and fibrin and dark layers of red cells, formed by thrombus growth in flowing blood, so they indicate antemortem thrombosis. Postmortem clots are gelatinous, with a dark 'currant jelly' lower part and yellow 'chicken fat' upper part, and are not attached to the wall.

Option by option

A. A postmortem clot
A postmortem clot is smooth, rubbery and unattached, without laminations.
B. An embolus from a distant site only
An embolus may also be laminated if a thrombus fragment, but adherence to the wall points to an in situ thrombus.
C. An antemortem thrombus with lines of Zahn (correct)
Correct. Layering and adherence indicate that the thrombus formed in flowing blood during life.
D. A fibrin cast formed after death
A fibrin cast formed after death would not show organised layers or attachment.

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, An antemortem thrombus with lines of Zahn. Lines of Zahn are alternating pale layers of platelets and fibrin and dark layers of red cells, formed by thrombus growth in flowing blood, so they indicate antemortem thrombosis.

Why is "A postmortem clot" not the answer?

A postmortem clot is smooth, rubbery and unattached, without laminations.

Why is "An embolus from a distant site only" not the answer?

An embolus may also be laminated if a thrombus fragment, but adherence to the wall points to an in situ thrombus.

Why is "A fibrin cast formed after death" not the answer?

A fibrin cast formed after death would not show organised layers or attachment.

What concept does this question test?

It tests Haemodynamics: thrombosis in Pathology. Postmortem clots are gelatinous, with a dark 'currant jelly' lower part and yellow 'chicken fat' upper part, and are not attached to the wall.

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 Haemodynamics: thrombosis?

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.