Neurocutaneous syndromes: practice question

A Dermatology 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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Dermatology · Neurocutaneous syndromes

Sample item

A 10-year-old has six light-brown macules larger than 5 mm on the trunk, axillary freckling and two cutaneous neurofibromas. Which ocular finding is most characteristic of this disorder?

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

The answer and the reasoning

C. Lisch nodules of the iris

Neurofibromatosis type 1 is autosomal dominant, due to NF1 gene mutations on chromosome 17, with six or more cafe-au-lait macules, axillary freckling, neurofibromas, optic glioma and iris Lisch nodules, which are melanocytic hamartomas. Lisch nodules appear in most adults with the disease.

Option by option

  • A. Kayser-Fleischer ring

    Kayser-Fleischer rings occur in Wilson's disease.

  • B. Cherry-red spot at the macula

    A cherry-red spot occurs in lysosomal storage diseases and in central retinal artery occlusion.

  • C. Lisch nodules of the iris (correct)

    Correct. Lisch nodules are characteristic of NF1.

  • D. Ectopia lentis

    Ectopia lentis is seen in Marfan syndrome and homocystinuria.

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.

More Dermatology questions

Questions about this Dermatology question

What is the answer to this Dermatology question?

The best answer is C, Lisch nodules of the iris. Neurofibromatosis type 1 is autosomal dominant, due to NF1 gene mutations on chromosome 17, with six or more cafe-au-lait macules, axillary freckling, neurofibromas, optic glioma and iris Lisch nodules, which are melanocytic hamartomas.

Why is "Kayser-Fleischer ring" not the answer?

Kayser-Fleischer rings occur in Wilson's disease.

Why is "Cherry-red spot at the macula" not the answer?

A cherry-red spot occurs in lysosomal storage diseases and in central retinal artery occlusion.

Why is "Ectopia lentis" not the answer?

Ectopia lentis is seen in Marfan syndrome and homocystinuria.

What concept does this question test?

It tests Neurocutaneous syndromes in Dermatology. Lisch nodules appear in most adults with the disease.

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 Neurocutaneous syndromes?

Learn each condition by its primary lesion, site and signature sign. Then use the flashcards and the other Dermatology 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.