Atypical breast hyperplasia is an overgrowth of breast cells where the cells look abnormal. It can happen in the lobules or ducts of the breast.
Although atypical breast hyperplasia is not cancer, your risk of cancer with this condition is about four to five times higher than the risk of someone without this condition.
If you have atypical breast hyperplasia, your doctor might recommend surgery to remove breast tissue and make sure it's not cancerous.