Firstly Borderter: don't panic!
My OH has had a couple of full abdominal ultrasounds done in the last year, related to a very large gallstone. Just the one, but it's a strangely big one.
Anyway, during the course of those US procedures, various things have been noted about his abdominal physiology, including a cyst in each kidney and one in his liver.
Allegedly they are quite common, and subject to their appearance and nature are often treated by a decent ignoring and periodic reviews.
Now, please don't take that statement as meaning you should ignore yours or not follow up to the full, but just sharing the feedback he was given on an unexpected finding. He did I have the longer discussions about the cysts, and agreed they would be monitored, so what I'm saying not all lumps and bumps are cause for concern, but are cause for investigation and understanding.
Good luck with it all, and let us know how you get along.