What are common causes for having a pulse in the abdomen of a 55-year-old woman?

A pulse was heard on a stethoscope by a doctor and I'm worried.

The large artery runs down there and if I lie down I can feel a pulse to the left of the belly button. This is normal. What did the Dr say? Or ask him what he thought may help.

Dr wants ultrasound and possibly ct. Called it a pulsating mass, I think. They might suspect it’s an abdominal aortic aneurysm, but my fear is actually that it could be cancer. There are no cancer symptoms though. This is the only indication of anything “odd”. Edit: I have no idea why those words are being hyperlinked- I didn’t hyperlink them.