Adaptation: metaplasia: 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.

Try it

Pathology · Adaptation: metaplasia

Sample item

A 3-year-old malnourished child with night blindness has Bitot spots. Biopsy of respiratory mucosa in such vitamin A deficiency shows keratinising squamous epithelium replacing ciliated columnar cells. What is the mechanism of this change?

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

The answer and the reasoning

D. Reprogramming of epithelial stem cells to differentiate along a squamous pathway

Metaplasia is a reversible replacement of one differentiated cell type by another, produced by reprogramming of stem cells or undifferentiated mesenchymal cells under altered cytokine and growth factor signals. Vitamin A deficiency, through lack of retinoic acid signalling, causes squamous metaplasia of respiratory and conjunctival epithelium. It is reversible if the stimulus is removed.

Option by option

  • A. Compensatory hyperplasia due to increased cell loss alone

    Hyperplasia is an increase in cell number, while metaplasia is a change of cell type.

  • B. Direct transformation of mature columnar cells into squamous cells

    Mature cells do not transdifferentiate directly; the new phenotype arises from stem cell redirection.

  • C. Neoplastic transformation of the basal layer

    Metaplasia is a reversible adaptation and is not neoplastic.

  • D. Reprogramming of epithelial stem cells to differentiate along a squamous pathway (correct)

    Correct. Stem cell reprogramming is the accepted mechanism of metaplasia.

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 Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is D, Reprogramming of epithelial stem cells to differentiate along a squamous pathway. Metaplasia is a reversible replacement of one differentiated cell type by another, produced by reprogramming of stem cells or undifferentiated mesenchymal cells under altered cytokine and growth factor signals.

Why is "Compensatory hyperplasia due to increased cell loss alone" not the answer?

Hyperplasia is an increase in cell number, while metaplasia is a change of cell type.

Why is "Direct transformation of mature columnar cells into squamous cells" not the answer?

Mature cells do not transdifferentiate directly; the new phenotype arises from stem cell redirection.

Why is "Neoplastic transformation of the basal layer" not the answer?

Metaplasia is a reversible adaptation and is not neoplastic.

What concept does this question test?

It tests Adaptation: metaplasia in Pathology. Vitamin A deficiency, through lack of retinoic acid signalling, causes squamous metaplasia of respiratory and conjunctival epithelium. It is reversible if the stimulus is removed.

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 Adaptation: metaplasia?

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.