A WLE can only be used for lesions up to 4 cm in diameter, as removal of any larger lesions could leave a visibly dented area in the breast. The extent of excision is variable, ranging from lumpectomy to quadrantectomy.
Due to the size limitation of a WLE (which is limited to lesions no bigger than 4 cm), removing larger lesions would result in a visible indentation on the breast.  The removal procedure can vary from a lumpectomy to a quadrantectomy, depending on the lesion's extent.