What percentage of cases of atypical hyperplasia go on to become breast cancer?
There is not a simple numerical answer to this question. First, atypical hyperplasia is a type of benign breast disease. There are two types of atypical hyperplasia: atypical ductal hyperplasia and atypical lobular hyperplasia. Furthermore, pathologists categorize atypical hyperplasia by varying degrees from minimal to well-developed. There are also other types of benign breast disease such as proliferative disease without atypia, nonproliferative disease, fibroadenoma and others which can influence the risk for breast cancer. Some studies suggest that women with atypical hyperplasia can have an elevated risk for breast cancer upwards of 1.5 -3 times higher than the average for her age (9-12).
