Al Unser was hospitalized in his hometown of Albuquerque last month for treatment of pancreatitis and gallstones

TSN.ca - Auto Racing - Canada's Sports Leader: "Unser was hospitalized in his hometown of Albuquerque last month for treatment of pancreatitis and gallstones, but the liver operation became necessary after a biopsy disclosed the tumor.
Doctors removed half of Unser's liver and his gall bladder in the Colorado procedure, his wife said. Gall bladder surgery initially had been scheduled for last month in New Mexico.

''But they never got that far with the gall bladder,'' Susan Unser said. ''They found the tumour when they did a CT scan. That's when they found his gallstones, but they also found this cancer.''"

Gallstones - MayoClinic.com

Gallstones - MayoClinic.com: "Like many people, you may have gallstones and not know it. In fact, gallstones - solid deposits of cholesterol or calcium salts that form in your gallbladder or nearby bile ducts - often cause no symptoms and require no treatment. But some people with gallstones will have a gallbladder attack that can cause symptoms such as nausea and an intense, steady ache in their upper middle or upper right abdomen. In some cases, the pain can be severe and intermittent."