In a chronic smoker, bronchi showed stratified squamous cells with underlying glands. What type of change is this?
Metaplasia Normally in bronchi -pseudostratified ciliated columnar epithelium is present. In chronic smoker,Replaced by -stratified squamous epithelium. This type of change in epithelium is called as Metaplasia. *Commonest connective tissue metaplasia is Myositis ossificans. *Metaplasia is a benign, reversible condition. Differentiation The extent to which neoplastic parenchymal cells resemble the corresponding normal parenchymal cells, both morphologically and functionally Lack of differentiation is called Anaplasia (hallmark of malignancy). Features of Anaplasia: Pleomorphism Tumor giant cells Atypical mitoses Loss of polarity Dysplasia Means "disordered growth." Dysplastic cells may exhibit considerable pleomorphism and often contain large hyperchromatic nuclei with a high nuclear-to-cytoplasmic ratio. Carcinoma in situ When dysplastic changes are marked and involve the full thickness of the epithelium But the lesion does not penetrate the basement membrane, it is considered a preinvasive neoplasm Fig:-Caracinoma in Situ A:- (Low power view) Atypical dysplastic cells B:-(High power view) Nuclear and cellular pleomorphism, and Mitotic figures seen
Metaplasia
Anaplasia
Dysplasia
Neoplasia
Basic Concepts