Section of a cystic mass isolated from the parotid gland

The parotid gland is the major salivary gland located on both sides of the mouth. This paraffin section has been stained with H+E (Hematoxylin and Eosin), which is the most common histological stain used for biopsies and to detect cancer. Hematoxylin stains basic structures such as DNA blue and Eosin stains acidic structures such as proteins red. The red, ringed structures seen in this image are known as Liesegang rings, and are formed by precipitation. In the case of cysts and abscesses, protein is sometimes precipitated around a central point which creates the observed round structures. In cytopathology they have been mistaken for parasites or their ova. Horizontal image width 215 micrometres.