C2 (benign)
This category indicates an adequate sample without evidence of significant atypia or malignancy.
Benign cases consist of monolayers of uniform ductal cells with round-oval shaped nuclei whose size is similar to that of red blood cells.
Dispersed individual and paired naked nuclei can be seeni in the background
If a cyst has been aspirated, then a mixture of foamy macrophages and regular apocrine cells may be part of the cytological picture.
Fragments of fibro-fatty tissue are also common findings.
To summarise
The main cytological criteria of benign lesions are:
Monolayer of uniform ductal cells
Appropriate cellular orientation
Good intercellular cohesion
Small sized nuclei (size similar to that of red blood cells)
Myoepithelial/stromal elements/naked bipolar nuclei