U/s for gallbladder polyp and liver cyst came back fine except said spleen mild enlarge 12.2 cm. I am 48 and 5"9. Scared what does this mean?

Nothing serious. Spleen size is somewhat variable in each person. So there is no serious condition which I can think of ,when a spleen is reported as "mildly enlarged" Any radiology report which says slight or mild abnormaility is mostly insignificant because a radilogist is not always sure of what may be normal or close to normal. So they often place a comment like this to cover themselves...purely defensive act!