Glossary — N

A needle biopsy is a procedure in which a doctor uses a hollow needle to remove a small amount of tissue or fluid from a suspicious area in the body. The sample is then examined by a pathologist under a microscope. Needle biopsy is less invasive than surgical biopsy and is the standard first approach for evaluating breast lumps and abnormalities seen on imaging.

Needle localization is a procedure performed before breast surgery to mark the exact location of an abnormality — such as a cluster of microcalcifications or a small mass — that cannot be felt by hand. A thin wire or other marker is inserted into the breast using imaging guidance so that the surgeon can locate and remove the precise area during the operation.

Neoadjuvant therapy refers to treatment — most often chemotherapy, targeted therapy, or hormone therapy — given before the primary surgical procedure to remove a tumor. In breast cancer, the goal is usually to shrink a large tumor enough to allow breast-conserving surgery, or to see how the cancer responds to a particular drug regimen before surgery.

Neuropathy refers to damage or dysfunction of the peripheral nerves — the nerves outside the brain and spinal cord that carry signals to and from the limbs and organs. Common symptoms include tingling, numbness, burning pain, or weakness, often starting in the hands and feet. In women's health, neuropathy is frequently encountered as a side effect of chemotherapy or as a feature of multiple sclerosis.

Nipple discharge refers to fluid that comes from the nipple when a woman is not pregnant or breastfeeding. It is a common breast symptom with many possible causes, most of which are benign. However, certain types of discharge — particularly spontaneous, bloody, or coming from one duct in one breast — warrant medical evaluation to rule out an underlying condition.

Node negative means that cancer cells were not found in the lymph nodes examined during surgery or biopsy. In breast cancer, this most often refers to the axillary (underarm) lymph nodes. Node-negative status is a favorable prognostic sign, generally indicating the cancer is less likely to have spread beyond the breast at the time of diagnosis.

Node positive means that cancer cells were found in one or more of the lymph nodes examined during surgery or biopsy. In breast cancer, this typically refers to the axillary (underarm) nodes. Node-positive status affects cancer staging and often influences decisions about the scope of surgery, radiation, and systemic treatments such as chemotherapy.

Nuclear medicine is a medical specialty that uses tiny amounts of radioactive substances called tracers to create images showing how organs and tissues are functioning, not just what they look like structurally. In women's health and oncology, nuclear medicine scans such as PET scans, bone scans, and sentinel lymph node procedures play important roles in diagnosing and staging disease.