Neoplasia: neuromuscular paraneoplastic syndromes: 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: neuromuscular paraneoplastic syndromes

Sample item

A 60-year-old male smoker has proximal leg weakness, dry mouth and diminished reflexes. Strength improves transiently after sustained contraction. A chest film shows a hilar mass. Which autoantibody is most likely to be found?

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

The answer and the reasoning

A. Antibodies to presynaptic voltage-gated calcium channels

Lambert-Eaton myasthenic syndrome is a paraneoplastic disorder, mostly with small cell lung carcinoma, in which antibodies against presynaptic calcium channels reduce acetylcholine release. Strength increases briefly after exercise or with repetitive stimulation, unlike myasthenia gravis.

Option by option

  • A. Antibodies to presynaptic voltage-gated calcium channels (correct)

    Antibodies to presynaptic calcium channels cause Lambert-Eaton syndrome associated with small cell carcinoma.

  • B. Antibodies to postsynaptic acetylcholine receptors

    Acetylcholine receptor antibodies cause myasthenia gravis, where weakness worsens with repeated use and thymoma may be present.

  • C. Anti-Hu antibodies against neuronal nuclei

    Anti-Hu antibodies cause paraneoplastic sensory neuronopathy and encephalomyelitis in small cell carcinoma.

  • D. Anti-Yo antibodies against Purkinje cells

    Anti-Yo antibodies cause paraneoplastic cerebellar degeneration, typically with ovarian and breast cancer.

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 Pathology question

What is the answer to this Pathology question?

The best answer is A, Antibodies to presynaptic voltage-gated calcium channels. Lambert-Eaton myasthenic syndrome is a paraneoplastic disorder, mostly with small cell lung carcinoma, in which antibodies against presynaptic calcium channels reduce acetylcholine release.

Why is "Antibodies to postsynaptic acetylcholine receptors" not the answer?

Acetylcholine receptor antibodies cause myasthenia gravis, where weakness worsens with repeated use and thymoma may be present.

Why is "Anti-Hu antibodies against neuronal nuclei" not the answer?

Anti-Hu antibodies cause paraneoplastic sensory neuronopathy and encephalomyelitis in small cell carcinoma.

Why is "Anti-Yo antibodies against Purkinje cells" not the answer?

Anti-Yo antibodies cause paraneoplastic cerebellar degeneration, typically with ovarian and breast cancer.

What concept does this question test?

It tests Neoplasia: neuromuscular paraneoplastic syndromes in Pathology. Strength increases briefly after exercise or with repetitive stimulation, unlike myasthenia gravis.

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: neuromuscular paraneoplastic syndromes?

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.