Can you solve a 40 year old mystery?

Once again I'm not sure where to post but I'll try here.

In the mid-1970's a friend found a lump in her breast. If mammos and things like that were around then they weren't in use here. Her doctor did a manual exam and said it was suspicious(because it was large, hard and immovable). He sent her to the hospital for a biopsy. Unusual in those days. When they found something like that they usually just went ahead and did a mastectomy. When they removed the thing they discovered it was dried up and shriveled. No one ever figured out what it was. She was given no further testing and given no treatment. I lost touch with her about ten years ago bu,t up to that time, the thing never came back and she remained cancer free. Any ideas what it was? I'm having my surgery next week and, quite frankly, I'm hoping something like this will happen to me. BTW, my friend was in her early 20's. In those days you never heard of anyone that young getting bc.