This information is provided by the National Institutes of Health (NIH) Genetic and Rare Diseases Information Center (GARD).
Cancer of the appendix is very rare and is typically found incidentally during appendectomies, in about 1% of the cases. According to a report published by the National Cancer Institute, using the Surveillance, Epidemiology, and End Results (SEER) database, appendix cancer account for about 0.4% of gastrointestinal tumors. There are several subytpes. The most common is the carcinoid type (66% of the total), with cyst-adenocarcinoma accounting for 20% and adenocarcinoma accounting for 10%. Then there are the rare forms of cancers which include adenocarcinoid, signet ring, non-Hodgkin’s lymphoma, ganglioneuroma, and pheochromocytoma. Benign primary tumors are mainly “mucinous epithelial neoplasms”, also called adenomas, cystadenoma, and benign neoplastic mucocele.
Adenocarcinoma of the appendix is a epithelial cancer of the appendix. The term ‘epithelium’ refers to cells that line hollow organs and glands and those that make up the outer surface of the body. Epithelial cells help to protect or enclose organs. Some produce mucus or other secretions. Types of adenocarcinoma of the appendix include mucinous adenocarcinoma, non-mucinous adenocarcinoma, and signet cell carcinoma of the appendix (which is the rarest, involving only 4% of all the subtypes of appendix cancer).
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