Just had a mammogram, the result says breast is heterogenously dense, which may obscure small masses, there is an indeterminate asymmetry seen in the right breast, what does it mean?

Probably OK: Standards for mammography results recently changed, with expert guidelines now advising that patients be informed if dense tissue makes it harder to see small abnormalties. However, the risk of this usually is very low. If you are at special risk (e.g. strong family history of breast cancer), your insurance may cover MRI to assure all is well. Discuss with your doctor and/or the radiologist.