What is "benign tumor"

Tumor \Tu"mor\, n. [L., fr. tumere to swell: cf. F. tume['u]r. See Tumid.]

1. (Med.) A morbid swelling, prominence, or growth, on any part of the body; especially, a growth produced by deposition of new tissue; a neoplasm.

2. Affected pomp; bombast; swelling words or expressions; false magnificence or sublimity. [R.]

   Better, however, to be a flippant, than, by a revolting form of tumor and perplexity, to lead men into habits of intellect such as result from the modern vice of English style.
   --De Quincey.

   Encysted tumor, a tumor which is inclosed in a membrane called a cyst, connected with the surrounding parts by the neighboring cellular substance.

   Fatty tumor. See under Fatty.

   Innocent tumor, or Benign tumor, one which does not of itself threaten life, and does not usually tend to recur after extirpation; a tumor which has not metastesized.

   Malignant tumor, a tumor which tends continually to spread, to become generalized in different parts of the body, and to recur after extirpation, and which, if left to itself, causes death.

n. A tumor which can usually be removed without serious complications and will not be fatal to the patient.

n. a tumor that is not cancerous [syn: benign tumour, nonmalignant tumor, nonmalignant tumour, nonmalignant neoplasm]

A benign tumor is a mass of cells ( tumor) that lacks the ability to invade neighboring tissue or metastasize. These characteristics are required for a tumor to be defined as cancerous and therefore benign tumors are non-cancerous. Also, benign tumors generally have a slower growth rate than malignant tumors and the tumor cells are usually more differentiated (cells have normal features). Benign tumors are typically surrounded by an outer surface (fibrous sheath of connective tissue) or remain with the epithelium. Common examples of benign tumors include moles and uterine fibroids.

Although benign tumors will not metastasize or locally invade tissues, some types may still produce negative health effects. The growth of benign tumors produces a " mass effect" that can compress tissues and may cause nerve damage, reduction of blood to an area of the body ( ischaemia), tissue death ( necrosis) and organ damage. The mass effect of tumors are more prominent if the tumor is within an enclosed space such as the cranium, respiratory tract, sinus or inside bones. Tumors of endocrine tissues may overproduce certain hormones, especially when the cells are well differentiated. Examples include thyroid adenomas and adrenocortical adenomas.

Although most benign tumors are not life-threatening, many types of benign tumors have the potential to become cancerous ( malignant) through a process known as tumour progression. For this reason and other possible negative health effects, some benign tumors are removed by surgery.