Adenocarcinoma of the appendix

The diagnosis of adenocarcinoma of the appendix is rarely made or suspected without surgery. It is often identified along with acute appendicitis. It may also be suspected after completing imaging of the appendix, such as a CT scan, and finding a right sided cystic mass. The diagnosis is usually confirmed through biopsy or evaluation of tissues under a microscope.

Yes. Types of adenocarcinoma of the appendix include mucinous adenocarcinoma (also known as cystadenocarcinoma) and non-mucinous adenocarcinoma (also known as colonic-type adenocarcinoma). Another type is the 'signet cell carcinoma of the appendix' which has a less favorable prognosis. This type has a high likelihood of having spread to adjacent organs (76%) by the time of diagnosis as compared to mucinous adenocarcinoma (63%) and the colonic type (37%).

Low grade appendix mucinous neoplasm (LAMN) is a well differentiated mucinous adenocarcinoma that arises from the appendix. Well differentiated means when the cells of the tumor and the organization of the tumor’s tissue are almost normal. A mucinous adencarcinoma is a type of cancer that produces what is called “mucin”, which is the main component of mucus. They begin to form on the lining cells “epithelial cells” on exocrine glands with lots of mucous. LAMN is characterized by slow growth and it is associated with the development of pseudomyxoma peritonei. Unlike the high grade mucinous adenocarcinoma of the appendix, it usually does not spread beyond the peritoneum (the membrane lining the cavity of the abdomen and covering the abdominal organs) and it does not spread (metastasize) to other sites of the body. Pseudomyxoma peritonei (PMP) is a condition that occur when the appendiceal mucinous tumors spread to the peritoneum. Treatment is with surgery removing the tumor, and may include chemotherapy. To learn how a tumor grade is determined visit the National Institute of Cancer link: Tumor Grade.

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).

The long-term outlook (prognosis) for adenocarcinoma of the appendix depends on the type and extent of the disease. Overall survival of adenocarcinoma of the appendix is approximately 60% at 5 years.

Adenocarcinoma of the appendix can be treated surgically, often by hemicolectomy. Appendicectomy may also be considered. Adjuvant chemotherapy may be beneficial for more advanced disease. There is a high incidence of secondary malignancy with adenocarcinomas of the appendix; as a result a careful pre- and post-operative evaluation is warranted. For additional information visit Cancer.net oncologist-approved information from the American Society of Clinical Oncology (ASCO): Appendix Cancer: Treatment Options

Cancer.Net, oncologist-approved cancer information from the American Society of Clinical Oncology, has information about appendix cancer. Click on the link to view the information.