Dear Holly: A general comment about nipple discharge. Many women have some type of nipple discharge or fluid when their breasts are squeezed, and its normal. Squeezing the nipple sends message to the brain and the pituitary gland responds by increasing prolactin levels, which in turn produces discharge from the nipple. The discharge can come in a variety of colors - gray, green and brown as well as white. Some women are more prone to more discharge including women on; birth control pills, certain blood pressure medications or on major tranquilizers. These medications increase prolactin levels in the body. There is also certain life periods when a person is more likely to get discharge than others: there may be more discharge at puberty and at menopause than the years in-between. The time to worry about nipple discharge is when it's spontaneous (comes out by itself without squeezing), keeps on happening,is only on one side, and/or if it is clear and sticky, like an egg white, or bloody. If these symptoms are present a doctor should check you.
Regarding your situation, without evaluation, it is impossible for us to speculate on what might be the cause of your discharge. There are certainly a variety of possibilities. You may consider an appointment with a medical breast specialist who can help to evaluate the situation. These are generally affiliated with large academic medical centers.
In the US, the recommendation for screening mammography is yearly, regardless of whether there are problems.
Thank you for all the information. I'll follow through with your suggestions and will probably go to the Mayo Clinic for further investigation even if the symptoms have subsided. Thanks again for your time. Holly