There are several kinds of appendix tumors, some of which are cancerous and some of which are not. The two main types of appendix cancer are called carcinoid tumors and carcinomas.
- Carcinoid tumors: Carcinoid tumors are the most common appendix cancers, making up about half of those diagnosed. They are usually found at the tip of the appendix. Because there are no symptoms, these tumors are often detected after the appendix has been removed. They are a type of gastrointestinal neuroendocrine tumor (NET).
Carcinomas. Carcinomas of the appendix include:
- Mucinous adenocarcinoma: These are the next most common type of appendix cancer. They begin in the appendix, but most of the time they are discovered after they have metastasized to the peritoneum (the lining of the abdominal cavity).
- Goblet cell carcinoids (also called adenocarcinoid tumors): These are less common tumors, which, despite the name, are not carcinoid tumors or NETs. They behave and are treated similarly to mucinous adenocarcinoma.
- Intestinal-type adenocarcinoma: These tumors are usually found near the bottom or base of the appendix. When these tumors cause symptoms, they are often like symptoms of colorectal cancer.
- Signet-ring cell adenocarcinoma: These are a very rare but aggressive type of appendix cancer. They often cause appendicitis.
There are numerous other precancerous appendix growths that may be found during appendectomy. Most are cured by removal of the organ alone, but some require follow up as they may have a small risk of recurrence.
One of these types of growths is appendiceal mucoceles, sacs or cysts on the appendix wall found on a CT scan. This type of lesion is not cancerous, but cancer cannot be ruled out unless they are removed.