A. Tumor Giant Cell
B. Atypical Mitotic Figure
Ans:B. Atypical Mitotic Figure
CYTOLOGICAL FEATURES OF NEOPLASTIC CELLS
- Loss of polarity. Normally, the nuclei of epithelial cells are oriented along the basement membrane which is termed as basal polarity. Early in malignancy, tumour cells lose their basal polarity so that the nuclei tend to lie away from the basement membrane .
- Pleomorphism. The term pleomorphism means variation in size and shape of the tumour cells.
- N:C ratio. Generally, the nuclei of malignant tumour cells show more conspicuous changes. Nuclei are enlarged disproportionate to the cell size so that the nucleocytoplasmic ratio is increased from normal 1:5 to 1:1.
- Anisonucleosis. Nuclei show variation in size and shape in malignant tumour cells .
- Hyperchromatism. Characteristically, the nuclear chromatin of malignant cell is increased and coarsely clumped. This is due to increase in the amount of nucleoprotein resulting in dark-staining nuclei, referred to as hyperchromatism .
- Nucleolar changes. Malignant cells frequently have a prominent nucleolus or nucleoli in the nucleus reflecting increased nucleoprotein synthesis .
- Mitotic figures. The parenchymal cells of poorly differentiated tumours often show large number of mitoses as compared with benign tumours and well-differentiated malignant tumours. These appear as either normal or abnormal mitotic figures:
- Normal mitotic figures may be seen in some non-neoplastic proliferating cells (e.g. haematopoietic cells of the bone marrow, intestinal epithelium, hepatocytes etc), in certain benign tumours and some low grade malignant tumours; in sections they are seen as a dark band of dividing chromatin at two poles of the nuclear spindle.
- Abnormal or atypical mitotic figures are more important in malignant tumours and are identified as tripolar, quadripolar and multipolar spindles in malignant tumour cells.
- Tumour giant cells. Multinucleate tumour giant cells or giant cells containing a single large and bizarre nucleus.
- Functional (Cytoplasmic) changes. Structural anaplasia in tumours is accompanied with functional anaplasia as appreciated from the cytoplasmic constituents of the tumour cells.
- Chromosomal abnormalities. Most malignant tumours show DNA aneuploidy, often in the form of an increase in the number of chromosomes, reflected morphologically by the increase in the size of nuclei.