Neoplasia: paraneoplastic polycythaemia: 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 · Neoplasia: paraneoplastic polycythaemia

Sample item

A 58-year-old man has haematuria, a flank mass and a haemoglobin of 18.9 g/dL with normal arterial oxygen saturation. CT shows a large renal mass invading the renal vein. What is the likely cause of his raised haemoglobin?

AJAK2 V617F mutation in the marrowBReduced plasma volume from dehydrationCEctopic erythropoietin production by the tumourDChronic hypoxia from lung metastases

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

The answer and the reasoning

C. Ectopic erythropoietin production by the tumour

Renal cell carcinoma can secrete erythropoietin and cause secondary polycythaemia, along with other paraneoplastic effects such as hypercalcaemia, fever and hypertension. Erythropoietin-secreting tumours also include hepatocellular carcinoma and cerebellar haemangioblastoma. Saturation is normal, so hypoxia is not the driver.

Option by option

A. JAK2 V617F mutation in the marrow
JAK2 mutation causes polycythaemia vera, in which erythropoietin levels are low.
B. Reduced plasma volume from dehydration
Dehydration produces a relative rise that does not account for a haemoglobin this high with a renal tumour.
C. Ectopic erythropoietin production by the tumour (correct)
Tumour erythropoietin production explains secondary polycythaemia with normal oxygen saturation.
D. Chronic hypoxia from lung metastases
Hypoxia from lung metastases would lower arterial saturation, which is normal here.

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, Ectopic erythropoietin production by the tumour. Renal cell carcinoma can secrete erythropoietin and cause secondary polycythaemia, along with other paraneoplastic effects such as hypercalcaemia, fever and hypertension.

Why is "JAK2 V617F mutation in the marrow" not the answer?

JAK2 mutation causes polycythaemia vera, in which erythropoietin levels are low.

Why is "Reduced plasma volume from dehydration" not the answer?

Dehydration produces a relative rise that does not account for a haemoglobin this high with a renal tumour.

Why is "Chronic hypoxia from lung metastases" not the answer?

Hypoxia from lung metastases would lower arterial saturation, which is normal here.

What concept does this question test?

It tests Neoplasia: paraneoplastic polycythaemia in Pathology. Erythropoietin-secreting tumours also include hepatocellular carcinoma and cerebellar haemangioblastoma. Saturation is normal, so hypoxia is not the driver.

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 Neoplasia: paraneoplastic polycythaemia?

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.