Macule: A small, flat, distinct colored area of skin that is less than 10 millimeters in diameter, and does not include a change in skin texture or thickness.
Maintenance therapy: Treatment that is given to help a primary (original) treatment keep working. Maintenance therapy is often given to help keep cancer in remission.
Malignancy: Cancerous; cells that can invade and destroy nearby tissue and spread to other parts of the body.
Malignant: Cancerous; cells that can invade and destroy nearby tissue and spread to other parts of the body.
Medical oncologist: See oncologist.
Melanin: A dark-brown to black pigment found in the skin, hair, and parts of the eyes.
Melanocyte: A cell in the skin and eyes that produces and contains the pigment called melanin.
Melanoma: A highly malignant type of skin cancer that arises in melanocytes, the cells that produce pigment. Melanoma usually begins in a mole.
Metastasis: The spread of cancer cells from their point of origin to other parts of the body by way of the bloodstream or the lymphatic system.
Metastatic melanoma: Melanoma that has spread to other parts of the body by way of the bloodstream or the lymphatic system.
Mole: A cluster of melanocytes and surrounding supportive tissue that usually appears as a tan, brown, or flesh-colored spot on the skin.
Mutation: A permanent change in the structure of a cell that may cause it to become cancerous.