Cysts in post menopausal women

Wife is 52yo caucasian with no history of breast cancer.  No history of breast cancer in family.  Partial hystorectomy 28 yrs ago. non smoker.  Early menopause.  Yearly mammogram showed what they believe to be
cyst(s).  FNA scheduled for next week.

Very little literature on this scenerio and would appreciate any insight you might be able to share, such as:
Likelihood of it being cancerous?
Where to find more information?

[CCF-RN,MSN-rf]

Dear Oracle:  Cysts are, by definition, benign fluid filled structures.  A simple aspiration, done in the doctors office, will confirm that, as it will disappear after the procedure.  If it is truly a cyst, there is very little chance of it being anything but benign.  Breast cysts can occur at any age.  You can read more by reading Dr. Susan Love's breast book.  It should be available at the library or local book store.

[Oracle]

Forgot to mention in my original post that she is on low dose HRT.

Thanks

[surgeon]

If these are something that show on mammogram, but are not feelable, then office aspiration can't be done. But usually, before doing aspiration, ultrasound is done: that can determine if they are fluid-filled, which proves they are cysts and are therefore harmless, and need no further treatment. There's really no reason to aspirate them if they can be shown to be cysts, and if they're not feelable