The ability to distinguish cancer cells from normal epithelial cells by light microscopy is fundamental for accurate cytological diagnosis. The principal morphological features which distinguish benign from malignant epithelial cells are summarised in the Table below.
|
Benign Cells |
Cancer Cells |
Cell size and shape |
Within physiological limits reflecting normal cell division and maturation of the epithelium |
Variation in size and shape reflecting abnormal cell division and maturation. |
Nuclear size |
Within normal limits reflecting normal cell division and maturation |
Significant variation in nuclear size
(anisonucleosis) reflecting abnormal cell division and maturation. . |
Nuclear shape |
Generally round, oval or bean shaped |
Abnormal shape |
Structure of chromatin in interphase nucleus
|
Finely granular chromatin evenly distributed throughout nucleus |
Coarse granular chromatin unevenly distribution throughout nucleus
|
Chromatin content of
interphase nucleus
|
Normal amount of chromatin for diploid cells evenly distributed in all cells. |
Chromatin often increased but the amount and distribution of chromatin varies from one nucleus to another due to abnormal cell division. |
Hyperchromasia |
Rarely seen, if present reflects regenerative change |
Common reflecting increased chromatin content or rapid cell turnover or both |
Multinucleation |
Not normally found. If present nuclei are of even size |
Not uncommon. Nuclei vary is size and shape |
Nucleoli |
Small , even size , few in number |
Large,irregular variable in size and shape and in number |
Cohesiveness |
Well formed cell junctions |
Loss of cohesiveness |
Mitoses |
Occasionally seen in basal layer of epithelium |
Abnormal mitoses frequently found
throughout epithelium |