An abnormal mass of tissue: "Tumors are a classic sign of inflammation, and can be benign or malignant (cancerous)."

There are dozens of different types of tumors. Their names usually reflect the kind of tissue they arise in, and may also tell us something about their shapes or how they grow; for example, a medulloblastoma is a tumor that arises from embryonic cells (a blastoma) in the inner part of the brain (the medulla)."

"Diagnosis depends on the type and location of the tumor."

"Tumor marker tests and tumor imaging may be used to diagnose patients and some tumors can be seen on the exterior of the skin or felt with the fingers or hands."

A benign round, firm growth which develops at the bifurcation (two branches) of the common carotid artery or either of the two arteries located in the front of the neck, through which blood from the heart goes to the brain: "A carotid-body tumor may cause dizziness, nausea, and vomiting if it impedes, or hinders, the flow of blood and if pressure is increased in the vascular system, or the circulatory system that transports blood in the body and which is composed of the heart, arteries, capillaries, and the veins."

1. A nonmalignant cystic tumor containing elements derived from the ectoderm; such as, hair, teeth, or skin.
2. Tumors consisting of displaced ectodermal structures along the lines of embryonic fusions, the walls being formed of epithelium-lined connective tissues, including skin appendages and containing keratin, sebum, and hair.
3. A benign cystic teratoma with skin, skin appendages, and their products as the most prominent components, usually involving the ovary or the skin.