33. Squamous metaplasia in bronchus

Page created on November 14, 2018. Last updated on January 17, 2019 at 17:13

Staining: HE

Organ: Bronchi, lymph node


We can see two cuts of a bronchus and two pieces of a lymph node.

The top bronchus is the best, so we’ll use that. Cartilage and submucosal glands are present. In a small part of the bronchus is the epithelium stratified squamous.

The lymph nodes show anthracosis.

Diagnosis: Squamous metaplasia in bronchus


  • Smoking


Cartilage and submucosal glands show us that we’re looking at a bronchus and not a bronchiolus.

Most of the epithelial is healthy, respiratory epithelium with goblet cells. Only a small part of the epithelium shows stratified non-keratinizing squamous epithelial metaplasia.

This type of metaplasia is characteristic in smokers and is a precancerous or preneoplastic lesion toward lung cancer.

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2 thoughts on “33. Squamous metaplasia in bronchus”

  1. Note that my teacher specified that metaplasia on it’s own can be an adaptation (in this case str. squamous better suited against smoke damage) and not a precancerous state necessarily. Dysplasia is a precancerous state and metaplasia could lead to dysplasia.

    1. While I agree that metaplasia is first and foremost an adaptational response to a change in environment do I slightly disagree that it’s not a precancerous state. Not all metaplasias are associated with pathology (the cervix undergoes metaplasia with aging), but most of them can progress into dysplasia which is definitely a precancerous state.

      It comes down to a matter of definition. Several sources consider metaplasia as a precancerous lesion, but I agree that not all of them are.

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