DysplasiaDysplasia is change in cell or tissue phenotype.

DYSPLASIA• Dysplasia (dys-, "difficulty“ plasis, "formation") is a

term used in pathology to refer to an abnormality of development.

• This generally consists of an expansion of immature cells (such as cells of the ectoderm), with a

corresponding decrease in the number and location of mature cells.

• Dysplasia is often indicative of an early neoplastic process.

• The term dysplasia is typically used

when the cellular abnormality is restricted to

the originating tissue, as in the case of an early, in-situ neoplasm.

Microscopic changes

• Dysplasia is characterised by four major pathological microscopic changes:

1.Anisocytosis (cells of unequal size)2.Poikilocytosis (abnormally shaped cells)3.Hyperchromatism (excessive pigmentation)4.Presence of mitotic figures (an unusual number of

cells which are currently dividing).

• Dysplasia is an abnormality of both differentiation and maturation.

• It is an alteration in adult cells characterized by variation in their size, shape and organization.

• It is a loss of uniformity of cells and loss in their structural orientation.

• Dysplasia encountered principally in

epithelium.

The dysplastic cells show:1. Pleomorphism: Variation in size & shape.

2. Increased nuclear cytoplasmic ratio: N= 1:5/1: 6Increased size of nucleus causes increased nuclear cytoplasmic ration.

3. Hyperchromasia: Increased chromatin content resulting in deeply stained nuclei.

4. Increased mitotic figures: but pattern is normal

5. Cytoplasmic abnormalities: lack of keratinization in squamous cells & lack of mucin in glandular epithelium.

6. Disorderly arrangement of cells basal layer to the surface layer.

• Dysplasia is associated with chronic inflammation or irritation. This is non-neoplastic proliferation which differs from neoplasia in that the growth of dysplastic cell is controlled and stops

when inciting stimulus ceases while the growth of neoplastic cell is uncontrolled that persists even after the cessation of the stimulus.

• Hyperplasia and metaplasia are not directly premalignant condition, but if they are severe and sustained, they may progress to dysplasia which carries the risk of conversion to malignancy.

•Dysplasia carries the high risk of conversion to malignant neoplasm.

Dysplasia- common sites

•Cervix• Lung•Oral Cavity, Esophagus•Gall bladder

Clinical Significance

• 1. Dysplasia is reversible when inciting stimulus is removed.• 2. Higher chances of neoplastic transformation.

Developmental Dysplasia

• It is a defective development of cells and tissues resulting in abnormal or primitive histiogenetic structure e.g., renal dysplasia.

Dysplasia Harsh Mohan

• Dysplasia means ‘disordered cellular development’, often accompanied with metaplasia and hyperplasia.

• Dysplasia occurs most often in epithelial cells.• Epithelial dysplasia is characterised by cellular

proliferation and cytologic changes.

Changes in dysplasia• 1. Increased number of layers of epithelial cells.• 2. Disorderly arrangement of cells from basal layer

to the surface layer.• 3. Loss of basal polarity i.e. nuclei lying away from

basement membrane.• 4. Cellular and nuclear pleomorphism.• 5. Increased nucleocytoplasmic ratio.• 6. Nuclear hyperchromatism.• 7. Increased mitotic activity.

Common Examples

•Uterine Cervix•Respiratory tract

• Dysplastic changes often occur due to chronic irritation or prolonged inflammation. On removal of the inciting stimulus, the changes may disappear.

• In a proportion of cases, however, dysplasia progresses into carcinoma in situ (cancer confined to layers superficial to basement membrane) or invasive cancer.

Dysplasia- SR• Dysplasia is a disorderly but non-

neoplastic proliferation. Dysplasia is encountered principally in the epithelia. It is a loss in the uniformity of individual cells and in their architectural orientation.

• Dysplastic cells exhibit considerable pleomorphism and often possess hyperchromatic nuclei that are abnormally large for the size of the cell.

• Mitotic figures are more abundant than usual.

• Frequently the mitoses appear in abnormal locations within the epithelium.

• In dysplastic stratified squamous epithelium, mitoses are not confined to the basal layers, where they normally occur, but may appear at all levels and even in surface cells.

• There is considerable architectural anarchy.

• For example, the usual progressive maturation of tall cells in the basal layer to flattened squames on the surface may

be lost and replaced by a disordered scrambling of dark basal appearing cells.

•When dysplastic changes are marked and involve the entire thickness of the epithelium, the lesion is referred to as carcinoma in situ, a pre-invasive stage of cancer.

• Although dysplastic changes are often found adjacent to foci of malignant transformation, and long-term studies of cigarette smokers show that epithelial dysplasia almost invariably antedates the appearance of cancer, the term dysplasia without qualification does not indicate cancer, and dysplasia do not necessarily progress to cancer.

• Mild to moderate changes that do not involve the entire thickness of epithelium may be reversible, and with removal of the putative inciting causes, the epithelium may revert to normal.