Glossary — L

Laparoscopy is a surgical approach in which a small camera (laparoscope) and specialized instruments are inserted through tiny incisions in the abdomen, allowing the surgeon to see and operate on internal organs without a large open incision. It is used for both diagnosis and treatment of gynecologic conditions including endometriosis, ovarian cysts, fibroids, and ectopic pregnancy.

LCIS, or lobular carcinoma in situ, refers to the presence of abnormal cells in the lobules — the milk-producing glands of the breast. Unlike DCIS, LCIS is not considered a true cancer or a direct precursor, but rather a marker indicating that a woman has a higher-than-average risk of developing invasive breast cancer in the future, in either breast.

A lesion is a broad medical term for any region of tissue that has been damaged, changed, or is otherwise abnormal compared to the surrounding tissue. Lesions can be caused by injury, infection, inflammation, or abnormal cell growth — including cancer. The word itself carries no implication about severity; a lesion may be entirely benign or require further investigation.

Lobular carcinoma refers to abnormal cell growth originating in the lobules — the glandular structures in the breast that produce milk. It includes both lobular carcinoma in situ (LCIS), a risk indicator in which abnormal cells remain within the lobules, and invasive lobular carcinoma (ILC), the second most common type of invasive breast cancer, in which cancer cells have broken out of the lobules into surrounding tissue.

A lumpectomy is a surgical procedure that removes a breast tumor along with a rim of healthy tissue around it, leaving the rest of the breast intact. It is also called breast-conserving surgery or wide local excision. For many women with early-stage breast cancer, lumpectomy followed by radiation provides equivalent survival outcomes to mastectomy while preserving the breast.

Lymph nodes are small, bean-shaped glands distributed throughout the body along the lymphatic vessels. They filter lymph fluid and contain immune cells that help fight infection and cancer. In breast cancer, whether cancer cells have reached the lymph nodes — particularly those in the underarm (axilla) — is one of the most important factors in staging and treatment planning.

Lymphedema is swelling that occurs when lymphatic fluid cannot drain properly and accumulates in the tissues. In women who have had breast cancer treatment — particularly surgery or radiation involving the underarm lymph nodes — lymphedema most commonly develops in the arm, hand, or chest on the treated side. It is a chronic condition, but it can be effectively managed with proper care.

Lymphoma is a type of cancer that starts in lymphocytes — the white blood cells that are part of the body's immune system — and typically involves the lymph nodes, spleen, thymus gland, or bone marrow. It is divided into two main categories: Hodgkin lymphoma and non-Hodgkin lymphoma. Lymphoma is one of the more treatable forms of cancer, particularly when caught at an early stage.