About the appendix
The appendix is a pouch-like tube that is attached to the cecum, which is the first section of the large intestine or colon. The appendix averages 10 centimeters (about 4 inches) in length and is considered part of the gastrointestinal (GI) tract. Generally thought to have no significant function in the body, the appendix may be a part of the lymphatic, exocrine, or endocrine systems.
Appendix cancer occurs when cells in the appendix become abnormal and multiply without control. These cells form a growth of tissue, called a tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant, meaning it can grow and spread to other parts of the body. Another name for this type of cancer is appendiceal cancer. A benign tumor means the tumor can grow but will not spread.
Types of appendix tumors
There are different types of tumors that can start in the appendix:
Carcinoid tumor. A carcinoid tumor starts in the hormone-producing cells that are normally present in small amounts in almost every organ in the body. A carcinoid tumor usually starts in either the GI tract or lungs, but it also may occur in the pancreas, a man’s testicles, or a woman’s ovaries. An appendix carcinoid tumor most often occurs at the tip of the appendix. Approximately 50% of all appendix tumors are carcinoid tumors. This type of cancer usually causes no symptoms until it has spread to other organs and often goes unnoticed until it is found during an examination or procedure performed for another reason. An appendix carcinoid tumor that remains confined to the area where it started has a high chance of successful treatment with surgery. Learn more about carcinoid tumors.
Appendiceal mucoceles. Mucoceles are swellings or sacs from swelling of the appendix wall, typically filled with mucous. There is a range of benign to malignant conditions that can occur in the appendix to form a mucocele. Two of these conditions are mucinous cystadenomas and mucinous cystadenocarcinomas. Mucinous cystadenomas are benign and do not spread and they are similar to adenomatous polyps that can develop in the colon. When contained in the appendix, they can be completely removed with surgery. However, if the appendix ruptures, the cells may spread in the body cavity and continue to secrete jelly-like substance called mucin in the abdomen. The build-up of mucin can lead to abdominal pain, bloating, and changes in bowel function including bowel obstruction (blockage). Mucinous cystadenocarcinomas can have similar effects with mucin in the abdomen but they are malignant, meaning they can spread to other parts of the body.
Colonic-type adenocarcinoma. Colonic-type adenocarcinoma accounts for about 10% of appendix tumors and usually occurs at the base of the appendix. This type of cancer looks and behaves like the most common type of colorectal cancer. It often goes unnoticed, and a diagnosis is frequently made during or after surgery for appendicitis. Appendicitis is inflammation of the appendix that can cause abdominal pain or swelling, loss of appetite, nausea, vomiting, constipation or diarrhea, inability to pass gas, or a low fever that begins after other symptoms.
Signet-ring cell adenocarcinoma. Signet-ring cell adenocarcinoma is very rare and considered to be more aggressive and more difficult to treat than other types of adenocarcinomas. This type of cancer usually occurs in the stomach or colon, and it can cause appendicitis when it develops in the appendix. It is called signet-ring cell adenocarcinoma because, under the microscope, the cell looks like it has a signet ring inside it.
Goblet cell carcinomas/Adenocarcinoids. Goblet cell carcinomas have features of both adenocarcinomas and carcinoid tumors. They are more aggressive than carcinoid tumors, and treatment is often similar to treatment for adenocarcinoma.
Paraganglioma. This is a rare tumor that develops from cells of the paraganglia, a collection of cells that come from nerve tissue that persist in small deposits after fetal (pre-birth) development, and is found near the adrenal glands and some blood vessels and nerves. This type of tumor is usually considered benign and is often successfully treated with the complete surgical removal of the tumor. Paraganglioma is very rare outside of the head and neck region.