This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on June 8, 2022.
Appendix cancer types are categorized based on the type of cells involved and what the cells look like under a microscope. The cell types are named for their behaviors, such as the likelihood of spreading to other parts of the body, the rate of growth and ability to be removed surgically.
The two main types of appendix cancer are called neuroendocrine tumors (NETs) and carcinomas.
Neuroendocrine tumors are the most common appendix cancers, making up about half of those diagnosed. They are most often found in women. These tumors begin in the hormone-producing cells and are typically found after the appendix has been removed. NETs in the appendix may also be referred to as carcinoid tumors.
Most NETs in the appendix are small and difficult to diagnose because they are not visible on routine imaging tests. Surgery is often the first-line appendix cancer treatment for NETs.
Carcinomas begin in the tissue that lines the appendix. Carcinomas of the appendix include those listed below.
The second most common type of appendix cancer, mucinous adenocarcinoma begins in the appendix and produces mucin, a jelly-like substance that may spread cancerous cells to other parts of the body. These tumors are often discovered after they have spread (metastasized) to the peritoneum (the lining of the abdominal cavity).
Goblet cell adenocarcinoma (also called Goblet cell carcinoid) tumors are less common. These types of appendiceal cancer behave and are treated similarly to mucinous adenocarcinoma. They are often more aggressive than carcinoid tumors and typically develop in patients between the ages of 50 and 55.
Also referred to as intestinal-type adenocarcinoma, these tumors account for about 10 percent of appendix tumors and are usually found near the base of the appendix. When these tumors cause symptoms, they often mimic the symptoms of colorectal cancer.
A very rare but aggressive type of appendix cancer, this type of cancer cell, when viewed under a microscope, looks like it has a signet ring inside it.
Next topic: What are the stages of appendix cancer?