Determining whether excision of all fibroepithelial lesions of the breast is needed to exclude phyllodes tumor: upgrade rate of fibroepithelial lesions of the breast to phyllodes tumor.

Fibroepithelial lesions (FELs) are a common histologic finding on core needle biopsy (CNB) of the breast. Fibroepithelial lesions include fibroadenoma and phyllodes tumor, which can be difficult to distinguish with an initial CNB. An institutional experience was reviewed from February 12, 2001, to January 4, 2007, to determine the safety of selective rather than routine excision of FELs and to determine the factors associated with upgrading diagnosis of FELs to phyllodes tumors without definitive phyllodes tumor diagnosis by CNB.