Hi,
Atypical Hyperplasia is a precancerous condition that affects cells in the breast. It describes an accumulation of abnormal cells in a breast duct. This condition isn't cancer, but it can be a forerunner to the development of breast cancer. Over the course of your lifetime, if the atypical hyperplasia cells keep dividing and become more abnormal, your condition may be reclassified as carcinoma in SITU or noninvasive breast cancer.
For this reason, doctors usually recommend surgery to remove all of the affected tissue and obtain clear margins, or recommend more frequent breast cancer screening and careful consideration of medications and other strategies to reduce breast cancer risk.
Best wishes and I hope this helps.