C5 (malignant)
This category indicates an adequate sample showing cells characteristic of carcinoma, or other malignancy. Malignancy should never be diagnosed on the basis of a single criterion. Combinations of the features listed in the following table will be always necessary to achieve the diagnosis.
Criterion |
Benign |
Malignant |
General characteristics |
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Cellularity |
Usually poor or moderate |
Usually high |
Cell to cell cohesion |
Good with large defined clusters of cells |
Poor with cell separation resulting in dissociated cells with cytoplasm or small groups of cells |
Cell arrangement |
Even, usually in flat sheets (monolayer) |
Irregular with overlapping and three-dimensional arrangement |
Cell types |
Mixtures of epithelial, myoepithelial and other cells with fragments of stroma |
Usually uniform cell population |
Bipolar (elliptical) naked nuclei |
Present, often in high numbers |
Not conspicuous |
Background |
Generally clean except in inflammatory conditions |
Occasionally with necrotic debris and sometimes inflammatory cells including macrophages |
Nuclear characteristics |
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Size (in relation to red blood cell (RBC) diameter) |
Small |
Variable, often large, depending on tumour type |
Pleomorphism |
Rare |
Common |
Nuclear membranes (Pap stain) |
Smooth |
Irregular with indentations |
Nucleoli (Pap stain) |
Indistinct or small and single |
Variable but may be prominent, large and multiple |
Chromatin (Pap stain) |
Smooth or fine |
Clumped and may be irregular |
Additional features |
Apocrine metaplasia, foamy macrophages |
Mucin, intracytoplasmic lumina |
(Modified from: GUIDELINES FOR NON-OPERATIVE DIAGNOSTIC PROCEDURES AND REPORTING IN BREAST CANCER SCREENING. NHSBSP Publication No 50 June 2001). |