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About the appendix
The appendix is a pouch-like tube that is attached to the cecum (the first section of the large intestine or colon). The appendix averages 10 centimeters (cm) 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 benign (noncancerous) or malignant (cancerous, meaning it can spread to other parts of the body). Another name for this type of cancer is appendiceal cancer.
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 starts primarily 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 66% 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 .
Mucinous cystadenocarcinoma. Mucinous cystadenocarcinoma is the most common non-carcinoid appendix tumor and accounts for about 20% of appendix cancer cases. This type of tumor produces a jelly-like substance called mucin that can fill the abdominal cavity and can cause abdominal pain, bloating, and changes in bowel function if the tumor breaks through the appendix or grows in the abdomen.
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 tumor 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 (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 (so called because, under the microscope, the cell looks like it has a signet ring inside it) is very rare and considered to be more aggressive and more difficult to treat than other types of adenocarcinomas. This type of tumor usually occurs in the stomach or colon, and it can cause appendicitis when it develops in the appendix.
Paraganglioma. Paraganglioma 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.
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