General pathology · Cell injury, adaptation and death
Metaplasia !
- Process
Metaplasia is when one mature cell type is replaced by another that better withstands the stress. It protects, but can lead to cancer.
Updated 2026-11-01
What it is
Metaplasia is a reversible change in which one differentiated cell type is replaced by another. It results from reprogramming of stem cells, not from mature cells changing type. The new tissue withstands the stress better but loses functions (for example, mucus and cilia in the airway). Persistent stress can lead from metaplasia to dysplasia and carcinoma.
Step by step
- Chronic irritation: acid, smoke, a stone, a parasite egg or a vitamin deficiency.
- Stem cells receive new signals from cytokines, growth factors and matrix.
- Transcription factors that define a different lineage are switched on (for example CDX2 for intestinal epithelium).
- A more resistant epithelium replaces the original one.
- If the stimulus stops, normal epithelium can return.
- If it persists, DNA damage accumulates: dysplasia and then carcinoma can follow.
Classic metaplasias
| Site | Change | Cause | Cancer risk |
|---|---|---|---|
| Distal esophagus (Barrett) | Squamous to intestinal columnar with goblet cells | Chronic acid reflux | Esophageal adenocarcinoma |
| Bronchi | Ciliated columnar to squamous | Cigarette smoke | Squamous cell carcinoma of the lung |
| Stomach | Gastric to intestinal glands | Chronic H. pylori gastritis | Intestinal-type gastric adenocarcinoma |
| Bladder | Urothelium to squamous | Schistosoma haematobium, stones | Squamous cell carcinoma of the bladder |
| Conjunctiva, airways | Columnar or transitional to keratinizing squamous | Vitamin A deficiency | None specific (dry eye, infections) |
| Cervix (transformation zone) | Columnar to squamous | Normal acidity after puberty | Site where HPV-driven lesions start |
Clinical notes
- In Colombia gastric cancer is among the leading causes of cancer death; intestinal metaplasia from chronic H. pylori gastritis is a step on that path.
- Patients with Barrett esophagus enter endoscopic surveillance with biopsies to detect dysplasia.
Test yourself
Think of the answer, then tap the question to see it.
What epithelium is seen in Barrett esophagus?
Intestinal-type columnar epithelium with goblet cells replacing the normal stratified squamous epithelium.
From which cells does metaplasia arise?
From reprogrammed stem or reserve cells, not from a change of mature differentiated cells.
What metaplasia does cigarette smoke cause in the bronchi, and what function is lost?
Squamous metaplasia; the ciliated mucus-producing epithelium is lost, so mucociliary clearance falls.
Related
- Dysplasia and carcinoma in situ
- Precancerous conditions: when chronic inflammation, metaplasia or hyperplasia raise the risk
- Hyperplasia: physiologic and pathologic
- Tobacco: how smoking injures tissue
- Multistep carcinogenesis: the adenoma–carcinoma sequence
Related conditions
- Barrett oesophagus
- Gastro-oesophageal reflux disease (GERD)
- Chronic obstructive pulmonary disease (COPD)
- Oesophageal cancer
- Lung cancer
- Vitamin A deficiency (night blindness and xerophthalmia)
- Schistosomiasis
- Bladder cancer
- Helicobacter pylori gastritis
- Gastric cancer
- Cervical intraepithelial neoplasia (cervical dysplasia)
Elsewhere in DurgiPedia
- Cell adaptations: hypertrophy, hyperplasia, atrophy, metaplasia
- Esophagus and the Barrett change
- The airway: from nose to bronchioles
- Simple, stratified, pseudostratified and transitional epithelium
- Stem cells and tissue renewal: labile, stable and permanent tissues
- Cervix and vagina: the transformation zone
- Vitamin A (retinol)
Microorganisms
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Barrett esophagus: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2024); Esophageal Cancer (StatPearls (NCBI Bookshelf), 2024); Vitamin A deficiency (World Health Organization, 2024).
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Representative model, for educational purposes only.