A common fibroadenoma is generally very, very unlikely to cause breast cancer, but a complex fibroadenoma increases the risk of breast cancer by 3-4 times. A complex fibroadenoma is diagnosed pathologically if it contains one or more of the following: a cyst > 0.3 cm in diameter, sclerosing adenopathy, epithelial calcification, or papillary sweat gland hyperplasia. Complex fibroadenomas are more common in middle-aged women over 40 years of age. Since the pathologic diagnosis of complex fibroadenoma can only be confirmed by postoperative pathology, surgical excision is currently recommended for all fibroadenomas found.