• The removal of a cancer as well as some of the breast tissue around the tumor and the lining over the chest muscles below the tumor. Usually some of the lymph nodes under the arm are also taken out. Also called partial mastectomy. (Cancer.gov)
  NCI Thesaurus
  U.S. National Cancer Institute, 2021
• (mastectomy, segmental) Removal of only enough breast tissue to ensure that the margins of the resected surgical specimen are free of tumor.
  NLM Medical Subject Headings
  U.S. National Library of Medicine, 2021
• Background Lumpectomy is defined as an excision of a breast lump with a surrounding rim of normal breast tissue, as shown in the image below. Traditionally, a lumpectomy was performed only to diagnose a breast mass.
  Medscape
  WebMD, 2019
• Lumpectomy (lum-PEK-tuh-me) is surgery to remove cancer or other abnormal tissue from your breast.
  Mayo Clinic
  Mayo Foundation for Medical Education and Research