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.
|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|
|Size (in relation to red blood cell (RBC) diameter)||Small||Variable, often large, depending on tumour type|
|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).
In many other European countries the diagnostic standardization all breast FNAs cytology specimens is coded using only four reporting categories:
- Suspicious and
When European and U.K. classifications are compared there are no differences in next-step diagnostic procedure between U.K C3, C4 and C5 categories and suspicious/malignant since histopathological evaluation is required.