Glossary Terms

Not normal. An abnormal lesion or growth may be cancer, premalignant (likely to become cancer), or benign (not cancer).

A thick, scaly patch of skin that may become cancer. It usually forms on areas exposed to the sun, such as the face, scalp, back of the hands, or chest. It is most common in people with fair skin. Also called senile keratosis and solar keratosis.

A small, round cell found in the lower part (or base) of the epidermis, the outer layer of the skin.

Cancer that begins in the lower part of the epidermis (the outer layer of the skin). It may appear as a small white or flesh-colored bump that grows slowly and may bleed. Basal cell carcinomas are usually found on areas of the body exposed to the sun. Basal cell carcinomas rarely metastasize (spread) to other parts of the body. They are the most common form of skin cancer. Also called basal cell cancer.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

Primary bone cancer is cancer that forms in cells of the bone. Some types of primary bone cancer are osteosarcoma, Ewing sarcoma, malignant fibrous histiocytoma, and chondrosarcoma. Secondary bone cancer is cancer that spreads to the bone from another part of the body (such as the prostate, breast, or lung).

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

The smallest type of blood vessel. A capillary connects an arteriole (small artery) to a venule (small vein) to form a network of blood vessels in almost all parts of the body. The wall of a capillary is thin and leaky, and capillaries are involved in the exchange of fluids and gases between tissues and the blood.

A group of abnormal cells that remain in the place where they first formed. They have not spread. These abnormal cells may become cancer and spread into nearby normal tissue. Also called stage 0 disease.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A measure of length in the metric system. There are 100 centimeters in a meter and 2½ centimeters in an inch.

Skin cancer that has spread down into the reticular dermis (the thick bottom layer of the dermis).

Skin cancer that has spread down into the subcutaneous tissue (tissue beneath the skin).

In medicine, a health problem with certain characteristics or symptoms.

Refers to cancer that has spread from the original (primary) tumor to distant organs or distant lymph nodes. Also known as distant metastasis.

The outer layer of the two main layers of the skin.

Cancer that has spread beyond the layer of tissue in which it developed and is growing into surrounding, healthy tissues. Also called infiltrating cancer.

The clear fluid that travels through the lymphatic system and carries cells that help fight infections and other diseases. Also called lymphatic fluid.

A rounded mass of lymphatic tissue that is surrounded by a capsule of connective tissue. Lymph nodes filter lymph (lymphatic fluid), and they store lymphocytes (white blood cells). They are located along lymphatic vessels. Also called lymph gland.

A thin tube that carries lymph (lymphatic fluid) and white blood cells through the lymphatic system. Also called lymphatic vessel.

The tissues and organs that produce, store, and carry white blood cells that fight infections and other diseases. This system includes the bone marrow, spleen, thymus, lymph nodes, and lymphatic vessels (a network of thin tubes that carry lymph and white blood cells). Lymphatic vessels branch, like blood vessels, into all the tissues of the body.

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

An instrument that is used to look at cells and other small objects that cannot be seen with the eye alone.

A measure of length in the metric system. A millimeter is one thousandth of a meter. There are 25 millimeters in an inch.

A bundle of fibers that receives and sends messages between the body and the brain. The messages are sent by chemical and electrical changes in the cells that make up the nerves.

Skin cancer that forms in the lower part of the epidermis (the outer layer of the skin) or in squamous cells, but not in melanocytes (skin cells that make pigment).

A thick, greasy, substance with no odor or taste made from petroleum (mixture of oily liquids found in the earth). Petroleum jelly is used on the skin to prevent drying and to help heal scrapes and burns. It is also used as a base for some ointments. Also called petrolatum.

The original tumor.

Energy released in the form of particle or electromagnetic waves. Common sources of radiation include radon gas, cosmic rays from outer space, medical x-rays, and energy given off by a radioisotope (unstable form of a chemical element that releases radiation as it breaks down and becomes more stable).

Cancer that forms in the tissues of the skin. There are several types of skin cancer. Skin cancer that forms in melanocytes (skin cells that make pigment) is called melanoma. Skin cancer that forms in the lower part of the epidermis (the outer layer of the skin) is called basal cell carcinoma. Skin cancer that forms in squamous cells (flat cells that form the surface of the skin) is called squamous cell carcinoma. Skin cancer that forms in neuroendocrine cells (cells that release hormones in response to signals from the nervous system) is called neuroendocrine carcinoma of the skin. Most skin cancers form in older people on parts of the body exposed to the sun or in people who have weakened immune systems.

The bones, muscles, tendons, and other tissues that reach from the base of the skull to the tailbone. The spine encloses the spinal cord and the fluid surrounding the spinal cord. Also called backbone, spinal column, and vertebral column.

Flat cell that looks like a fish scale under a microscope. These cells cover inside and outside surfaces of the body. They are found in the tissues that form the surface of the skin, the lining of the hollow organs of the body (such as the bladder, kidney, and uterus), and the passages of the respiratory and digestive tracts.

Cancer that begins in squamous cells, which are thin, flat cells that look like fish scales. Squamous cells are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the passages of the respiratory and digestive tracts. Also called epidermoid carcinoma.

The extent of a cancer in the body. Staging is usually based on the size of the tumor, whether lymph nodes contain cancer, and whether the cancer has spread from the original site to other parts of the body.

Abnormal cells are found in the squamous cell or basal cell layer of the epidermis (topmost layer of the skin). These abnormal cells may become cancer and spread into nearby normal tissue. Also called nonmelanoma carcinoma in situ.

The tumor is not larger than 2 centimeters at its widest point and may have one of the following high-risk features: (1) is thicker than 2 millimeters; (2) has spread into the lower layer of the dermis or into the layer of fat below the skin; (3) has grown and spread along nerve pathways; (4) began on an ear or on a lip that has hair on it; or (5) has cells that look very different from normal cells under a microscope.

The tumor is larger than 2 centimeters at its widest point; or the tumor is any size and has two or more of the following high-risk features: (1) is thicker than 2 millimeters; (2) has spread into the lower layer of the dermis or into the layer of fat below the skin; (3) has grown and spread along nerve pathways; (4) began on an ear or on a lip that has hair on it; or (5) has cells that look very different from normal cells under a microscope.

The tumor has spread to the jaw, eye socket, or side of the skull. Cancer may have spread to one lymph node on the same side of the body as the tumor. The lymph node is not larger than 3 centimeters; or, cancer has spread to one lymph node on the same side of the body as the tumor. The lymph node is not larger than 3 centimeters and one of the following is true: (1) the tumor is not larger than 2 centimeters at its widest point and may have one high-risk feature (is thicker than 2 millimeters, has spread into the lower layer of the dermis or the layer of fat below the skin, has grown and spread along nerve pathways, began on an ear or on a lip that has hair on it, or has cells that look very different from normal cells under a microscope); (2) the tumor is larger than 2 centimeters at its widest point; or (3) the tumor is any size and has two or more high-risk features (is thicker than 2 millimeters, has spread into the lower layer of the dermis or the layer of fat below the skin, has grown and spread along nerve pathways, began on an ear or on a lip that has hair on it, or has cells that look very different from normal cells under a microscope).

The tumor is any size and may have spread to the jaw, eye socket, or side of the skull. Cancer has spread to one lymph node on the same side of the body as the tumor and the affected node is larger than 3 centimeters but not larger than 6 centimeters, or cancer has spread to more than one lymph node on one or both sides of the body and the affected nodes are not larger than 6 centimeters; or, the tumor is any size and may have spread to the jaw, eye socket, skull, spine, or ribs. Cancer has spread to one lymph node that is larger than 6 centimeters; or, the tumor is any size and has spread to the base of the skull, spine, or ribs. Cancer may have spread to the lymph nodes; or, cancer has spread to distant parts of the body.

Performing exams and tests to learn the extent of the cancer within the body, especially whether the disease has spread from the original site to other parts of the body. It is important to know the stage of the disease in order to plan the best treatment.

A group or layer of cells that work together to perform a specific function.

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

A blood vessel that carries blood to the heart from tissues and organs in the body.

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