Preneoplastic changes of respiratory epithelium

Squamous cell carcinoma of the lung is preceded by precursor lesions, with a progression from benign squamous metaplasia, through dysplasia, to invasive cancer. Most authors acknowledge degrees (mild, moderate, severe) of dysplasia. The risk of developing bronchogenic carcinoma increases with the degree of atypia.

Preinvasive lesions

  • Squamous dysplasia
  • Carcinoma in situ
  • Atypical adenomatous hyperplasia
  • Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia
Squamous metaplasia
Squamous metaplasia
Squamous metaplasia
Squamous metaplasia

 

Squamous metaplasia
Atypical squamous metaplasia
Atypical squamous metaplasia

 

Atypical squamous metaplasia
Atypical squamous metaplasia
Atypical squamous metaplasia
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