Abortion - The removal of an embryo or foetus from the uterus, either by natural expulsion or by human intervention, before it is considered to be viable.
Abruption placentae - Bleeding from the placenta after the 28th week of pregnancy, which may result in the placenta becoming completely or partially detached from the wall of the uterus.
Abscess - A collection of pus from infection.
Acinus/ Acini - The parts of the breast gland where fluid or milk is produced
Acute - Occurring suddenly or over a short period of time. Sharp or intense.
Adjunctive (adjuvant) therapy - A secondary treatment in addition to the primary therapy. For example, chemotherapy is often an adjunctive therapy to mastectomy.
Adjuvant - Auxiliary, an aid to remove or prevent disease.
Adjuvant chemotherapy - The use of anticancer drugs after surgery to prevent a recurrence of cancer. For women with breast cancer, the most important indication for adjuvant chemotherapy is the spread of the cancer to the lymph nodes in the woman's underarm (axillary lymph nodes).
Advanced breast cancer - Stage of cancer in which the disease has spread from the breast to other body systems by traveling through the bloodstream or lymphatic system.
Afterbirth - A mass of tissue that consists of the placenta, umbilical cord and membranes, detached and expelled from the womb (uterus) during the third stage of labour following a birth.
AIDS - The acronym for Acquired Immune Deficiency Syndrome caused by the human immunodeficiency virus, known as HIV, a ribonucleic acid (RNA) retrovirus.
Allergens - Any substance that causes manifestations of allergies (abnormal and individual hypersensitivity to substances that are ordinarily harmless).
Alopecia - Absence or loss of hair.
Amenorrhoea - An absence of menstruation, which is normal before puberty, during pregnancy and while breast-feeding is being carried out, and following the menopause.
Amino acids - The building blocks of proteins and the end products of protein digestion.
Amniocentesis - A procedure carried out to sample the amniotic fluid surrounding a foetus. It is usually carried out between the 16th and 20th week of pregnancy if a foetal abnormality is suspected.
Amniotic fluifl - The liquid in the amniotic cavity, which is clear and composed mainly of water containing foetal cells, lipids and urine from the foetus. The amniotic fluid ('waters') is released when the membranes rupture during labour.
Analgesic - Medicine to control or relieve pain; example of Aspirin or Tylenol
Ancillary - Additional, auxiliary.
Androgen - A male sex hormone. Androgens may be used in patients with breast disease to treat symptoms of the disease.
Anesthesia - Medication that causes entire or partial loss of feeling or sensation.
Aneuploid - Cells with an atypical amount of DNA.
Angiogenesis - Development of blood vessels.
Anterior axillary fold - Fold created where the breast and arm meet at the front of the armpit area. The large chest muscle (pectoralis major), which extends from the chest to the upper arm, is the main component of this fold.
Apgar score - A method of assessing the health of an infant immediately after birth, carried out at one minute and five minutes after delivery.
Apoptosis - Disintegration of cells into membrane-bound particles that are destroyed by other cells.
Areola - The circle of pigmented skin on the breast that surrounds the nipple.
Artificial insemination - Semen collected from a donor is inserted by means of an instrument into the vagina of a woman in the hope that she will conceive. The semen may be from her husband or partner (AIH) or from an anonymous donor (AID) and is introduced near the time of ovulation. Usually AIH is used where the partner is impotent and AID when he is sterile.
Aspirate - To remove or withdraw fluid or tissue from a cavity by applying suction.
Aspiration - Removing fluid or cells from tissue by inserting a needle into an area and drawing the fluid into the syringe.
Assay - Analysis of a substance.
Asymmetric - Off balance. When one side does not match the other.
Asymptomatic - Without obvious signs or symptoms of disease. Cancer may cause symptoms and warning signs; but, especially in its early stages, cancer may develop and grow without producing any symptoms.
Atypia - Change in a cell that suggests a tendency toward malignant transformation.
Atypical - Not conforming to a regular type.
Atypical Cells - Not usual; abnormal. Cancer is the result of a typical cell division.
Atypical hyperplasia - Excessive growth of cells, some of which are abnormal.
Atypical lobular hyperplasia - Abnormally shaped cells proliferating excessively in the normal tissue arrangement of a breast lobule.
Augmentation mammaplasty (breast augmentation) - An operation to enlarge a woman's breast, usually by placing a silicone breast implant behind the breast.
Autologous - From the same person. An autologous blood transfusion is blood removed and then transfused back into the same person at a later date.
Autologous bone marrow transplantation - Removal of a person's bone marrow to allow for high-dose chemotherapy; the same marrow is replaced after chemotherapy.
Autologous flap breast reconstruction - Breast reconstruction with a woman's own natural tissues. Common donor sites for flaps are the abdomen, back, buttocks, and thigh.
Autosomal dominant gene - Non-sex-based gene that requires only one copy in order to be expressed.
Autosomal recessive gene - Non-sex-based gene that requires two copies in order to be expressed.
Autosome - Any chromosome other than a sex chromosome.
Axilla - The armpit area behind the anterior axillary's fold. It contains the axillary's lymph nodes.
Axillary dissection - Surgical removal of lymph nodes from the armpit. This tissue is then sent to a pathologist to determine if the breast cancer has spread.
Axillary Nodes - The lymph nodes in the axilla (underarm) that are removed during surgery to see ifthe cancer has spread beyond the breast. The number of nodes in this area varies in different women.
Axillary Tall - The portion of the breast extending into the area of the armpit.