What is appendiceal cancer? What to know about symptoms and causes after Adan Canto's death

Actor Adan Canto, known for his roles in "Designated Survivor" and "X-Men: Days of Future Past," died Monday at  age 42 after a battle with appendiceal cancer.

Appendiceal or appendix cancer is a rare cancer that grows from cells that make up the appendix, explains the National Cancer Institute. The appendix is a small pouch of tissue in the abdomen, connected to the large intestine.

In the U.S., appendiceal cancer "has been thought to affect about 1 or 2 people per 1 million per year. However, recent studies show that appendiceal cancer is becoming more common," the National Cancer Institute says on its website.