Breast cysts, like cysts elsewhere in the body, can be classified as either simple or complex.
Simple Cysts (fluid filled sacs) have virtually no chance of containing malignancy. They do not need to be aspirated unless they are causing discomfort and they do not need short-interval follow-up.Simple cyst do not turn into cancer.
Complex cysts however, are also fluid filled sacs but contain some solid material (debris) and that is why a fine needle aspiration is recommended to have the cells examined to better evaluate the nature of the cyst.
The majority of complex cysts are of benign nature though and you shouldn't be worried so much about it...I hope that the biopsy result will state that the complex cyst is BENIGN!
Best wishes to both you and your wife...
I'm not a doctor but I can share my experience. I was diagnosed with DCIS breast cancer on Nov 11th, yes, less than a month ago. I can tell you from all my testing nand talks with doctors, radiologists, oncologists that some cysts look benign (round and smooth) and others are not...they seem to have a few sharp edges. If it is an option, a second opinion is extremely valuable. Also, get copies of all test results and pathology results and carry them with you at all times when seeing medical professionals. There have been many appointments that would have been on hold until receipt of some report from another doctor. Take a deep breath, hug your wife and don't let the scariness get the best of you. I have had almost a month of such high stress and sleeplessness. Second opinion is my opinion