Skin pathology: 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 · Skin pathology

Sample item

A middle-aged patient has flaccid blisters, painful oral erosions and a positive Nikolsky sign. What does direct immunofluorescence of perilesional skin show?

ALinear IgG and C3 along the basement membraneBGranular IgA in the dermal papillaeCGranular immunoglobulin and complement band at the dermo-epidermal junctionDIgG deposited between keratinocytes in a net-like pattern

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

The answer and the reasoning

D. IgG deposited between keratinocytes in a net-like pattern

This is pemphigus vulgaris, caused by IgG against desmoglein 3 and sometimes desmoglein 1, producing suprabasal acantholysis. Immunofluorescence shows intercellular IgG, described as a fishnet or chicken-wire pattern.

Option by option

A. Linear IgG and C3 along the basement membrane
Linear basement membrane IgG and C3 is bullous pemphigoid, which has tense blisters.
B. Granular IgA in the dermal papillae
Granular IgA in dermal papillae indicates dermatitis herpetiformis.
C. Granular immunoglobulin and complement band at the dermo-epidermal junction
A granular band at the junction is the lupus band of systemic lupus erythematosus.
D. IgG deposited between keratinocytes in a net-like pattern (correct)
Autoantibodies against desmosomal cadherins coat the keratinocyte surfaces.

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 D, IgG deposited between keratinocytes in a net-like pattern. This is pemphigus vulgaris, caused by IgG against desmoglein 3 and sometimes desmoglein 1, producing suprabasal acantholysis.

Why is "Linear IgG and C3 along the basement membrane" not the answer?

Linear basement membrane IgG and C3 is bullous pemphigoid, which has tense blisters.

Why is "Granular IgA in the dermal papillae" not the answer?

Granular IgA in dermal papillae indicates dermatitis herpetiformis.

Why is "Granular immunoglobulin and complement band at the dermo-epidermal ju…" not the answer?

A granular band at the junction is the lupus band of systemic lupus erythematosus.

What concept does this question test?

It tests Skin pathology in Pathology. Immunofluorescence shows intercellular IgG, described as a fishnet or chicken-wire pattern.

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 Skin pathology?

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.