Pigmentary disorders: lichen planus pigmentosus: 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 · Pigmentary disorders: lichen planus pigmentosus

Sample item

A 35-year-old Indian woman has slowly progressive, asymptomatic, ill-defined slate-brown macules on the face and neck, with no preceding scaling or blisters. Biopsy shows basal vacuolar change and dermal melanophages. What is the diagnosis?

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

The answer and the reasoning

C. Lichen planus pigmentosus

Lichen planus pigmentosus presents as dark brown to grey macules in sun-exposed and flexural areas in skin of colour, and histology shows interface change with melanin incontinence. Treatment includes photoprotection, topical tacrolimus and sometimes oral agents. It is more refractory than melasma.

Option by option

  • A. Melasma

    Melasma lacks interface change on biopsy.

  • B. Addison disease

    Addison disease causes diffuse tanning with mucosal pigmentation.

  • C. Lichen planus pigmentosus (correct)

    Correct. This is lichen planus pigmentosus.

  • D. Pityriasis versicolor

    Pityriasis versicolor shows fine scaling and fungal elements.

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 Dermatology question

What is the answer to this Dermatology question?

The best answer is C, Lichen planus pigmentosus. Lichen planus pigmentosus presents as dark brown to grey macules in sun-exposed and flexural areas in skin of colour, and histology shows interface change with melanin incontinence.

Why is "Melasma" not the answer?

Melasma lacks interface change on biopsy.

Why is "Addison disease" not the answer?

Addison disease causes diffuse tanning with mucosal pigmentation.

Why is "Pityriasis versicolor" not the answer?

Pityriasis versicolor shows fine scaling and fungal elements.

What concept does this question test?

It tests Pigmentary disorders: lichen planus pigmentosus in Dermatology. Treatment includes photoprotection, topical tacrolimus and sometimes oral agents. It is more refractory than melasma.

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 Pigmentary disorders: lichen planus pigmentosus?

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.