Signet ring cells

Signet ring cells are round, discohesive (they don’t stick together) cancerous cells filled with a light blue coloured substance called mucin. The mucin tends to push the nucleus (the part of the cell that holds the genetic material) to the side (pathologists describe these nuclei as ‘eccentric’ or ‘peripheral’). Signet ring cells are epithelial cells; however, unlike most other types, they do not stick together.

Some types of cancer, such as invasive lobular carcinoma of the breast, are almost always made up of signet ring cells, and their presence does not change the behavior of the tumour. However, for other types of cancer, these cells are a sign that the tumour has become poorly differentiated, and these tumours tend to behave much more aggressively over time. Types of cancers that often show this change include adenocarcinoma of the stomach and adenocarcinoma of the colon.