Signet Ring Cells: Definition

Signet ring cells are abnormal cells seen in certain types of cancer. They get their name from their shape: each cell is filled with a substance called mucin, which pushes the cell’s nucleus (the part that holds genetic material) to the side, creating an appearance similar to a ring with a gemstone. Unlike most other types of cells, signet ring cells do not stick tightly together (they are described as discohesive).

Why are signet ring cells important?

Identifying signet ring cells helps pathologists diagnose certain cancers and better understand how a tumor may behave. For some cancers, the presence of signet ring cells doesn’t significantly change the tumor’s behavior. However, for other cancers, signet ring cells indicate that the tumor has become more abnormal (poorly differentiated) and more aggressive. Recognizing these cells is important because it helps guide treatment decisions and informs prognosis.

What types of cancer have signet ring cells?

Signet ring cells can be found in several types of cancer, including:

• Invasive lobular carcinoma of the breast: This type of breast cancer almost always contains signet ring cells. In this cancer, the presence of these cells does not usually change how aggressive the tumour is or how it is treated.

• Stomach (gastric) adenocarcinoma and colon adenocarcinoma: When signet ring cells are found in these cancers, it often signals that the tumour is more aggressive and likely to spread quickly, requiring a more intensive treatment approach.

How do pathologists identify signet ring cells?

Pathologists identify signet ring cells by carefully examining tissue samples under a microscope. They look for the distinctive features of these cells—round shape, mucin-filled appearance, and nuclei pushed off to the side. Special stains and additional testing may also be used to confirm the presence of mucin in the cells.

How does finding signet ring cells affect treatment?

When signet ring cells are found, especially in cancers of the stomach or colon, doctors may recommend more aggressive treatment plans, including surgery, chemotherapy, and possibly radiation therapy. The treatment will depend on the type of cancer, how far it has spread, and your overall health.

Questions to ask your doctor

If your pathology report mentions signet ring cells, you may want to ask your doctor:

• What does the presence of signet ring cells mean for my diagnosis and treatment?

• Do signet ring cells make my cancer more aggressive?

• How will finding these cells influence my treatment options and prognosis?

• Will I need additional tests or treatments due to the presence of signet ring cells?

Understanding what signet ring cells are and their significance can help you feel informed and actively involved in your medical care.