Benign tumor


Benign tumor

A benign tumor is a tumor that lacks all three of the malignant properties of a cancer. Thus, by definition, a benign tumor does not grow in an unlimited, aggressive manner, does not invade surrounding tissues, and does not metastasize. Common examples of benign tumors include moles and uterine fibroids.

The term "benign" implies a mild and nonprogressive disease, and indeed, many kinds of benign tumor are harmless to the health. However, some neoplasms which are defined as 'benign tumors' because they lack the invasive properties of a cancer, may still produce negative health effects. Examples of this include tumors which produce a "mass effect" (compression of vital organs such as blood vessels), or "functional" tumors of endocrine tissues, which may overproduce certain hormones (examples include thyroid adenomas, adrenocortical adenomas, and pituitary adenomas).

Benign tumors typically are encapsulated, which inhibits their ability to behave in a malignant manner. Nonetheless, many types of benign tumors have the potential to become malignant and some types, such as teratoma, are notorious for this.

Classification

The term "tumor" literally means "swelling", and the broadest definition of "benign tumor" encompasses all abnormal tissue masses which are not cancers. In practice, most of these entities are neoplasms, meaning that they contain a discrete population of cells which proliferate in an independent manner, usually as the result of acquired genetic abnormalities. Entities which may be referred to as "tumors" but are non-neoplastic include developmental abnormalities, such as "hamartomas" and "ectopic rests" (normal tissue in an anatomically abnormal location).cite book |author=Ramzi Cotran, Vinay Kumar, Tucker Collins |title=Robbins Pathologic Basis of Disease, 6th Edition |year=1999 |publisher=W.B. Saunders |isbn=072167335X |pages=]

Benign neoplasms are typically composed of cells which bear a strong resemblance to a normal cell type in their organ of origin. These tumors are named for the cell or tissue type from which they originate, followed by the suffix "-oma" (but not -carcinoma, -sarcoma, or -blastoma, which are generally cancers). For example, a "lipoma" is a common benign tumor of fat cells (lipocytes), and a "chondroma" is a benign tumor of cartilage-forming cells (chondrocytes). "Adenomas" are benign tumors of gland-forming cells, and are usually specified further by their cell or organ of origin, as in "hepatic adenoma" (a benign tumor of "hepatocytes", or liver cells). There are a few cancers with 'benign-sounding' names which have been retained for historical reasons, including "melanoma" (a cancer of pigmented skin cells, or melanocytes) and "seminoma" (a cancer of male reproductive cells).cite book |author=Ramzi Cotran, Vinay Kumar, Tucker Collins |title=Robbins Pathologic Basis of Disease, 6th Edition |year=1999 |publisher=W.B. Saunders |isbn=072167335X |pages=]

In some cases, certain "benign" tumors may later give rise to malignant cancers, which result from additional genetic changes in a subpopulation of the tumor's neoplastic cells. A prominent example of this phenomenon is the "tubular adenoma", a common type of colon polyp which is an important precursor to colon cancer. The cells in tubular adenomas, like most tumors which frequently progress to cancer, show certain abnormalities of cell maturation and appearance collectively known as dysplasia. These cellular abnormalities and are not seen in benign tumors that rarely or never turn cancerous, but are seen in other pre-cancerous tissue abnormalities which do not form discrete masses, such as pre-cancerous lesions of the uterine cervix. Some authorities prefer to refer to dysplastic tumors as "pre-malignant", and reserve the term "benign" for tumors which rarely or never give rise to cancer.

igns and symptoms

Benign tumors are very diverse, and may be asymptomatic or may cause specific symptoms depending on their anatomic location and tissue type. Symptoms or pathological effects of some benign tumors may include:
* Bleeding or occult blood loss causing anemia
* Pressure causing pain or dysfunction
* Cosmetic changes
* Itching
* 'Hormonal syndromes' resulting from hormones secreted by the tumor
* Obstruction, e.g., of the intestines
* Compression of blood vessels or vital organs

Treatment

Many benign tumors do not need to be treated at all. If a benign tumor is causing symptoms, presents a health risk, or causes a cosmetic concern for the patient, surgery is usually the most effective approach. Most benign tumors do not respond to chemotherapy or radiation therapy, although there are exceptions.

References


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • 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. [1913 Webster] 2.… …   The Collaborative International Dictionary of English

  • benign tumor — tumor which is not cancerous, tumor which is not malignant …   English contemporary dictionary

  • benign tumor — noun a tumor that is not cancerous • Syn: ↑benign tumour, ↑nonmalignant tumor, ↑nonmalignant tumour, ↑nonmalignant neoplasm • Hypernyms: ↑tumor, ↑tumour, ↑neoplasm …   Useful english dictionary

  • benign tumor — noun A tumor which can usually be removed without serious complications and will not be fatal to the patient …   Wiktionary

  • benign tumor — a tumor that lacks the properties of invasiveness and metastasis and is usually surrounded by a fibrous capsule; its cells also show a lesser degree of anaplasia than those of malignant tumors. Called also innocent t …   Medical dictionary

  • benign tumor — A noncancerous growth that does not invade nearby tissue or spread to other parts of the body …   English dictionary of cancer terms

  • 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. [1913 Webster] 2. Affected… …   The Collaborative International Dictionary of English

  • tumor — noun an abnormal new mass of tissue that serves no purpose (Freq. 18) • Syn: ↑tumour, ↑neoplasm • Derivationally related forms: ↑neoplastic (for: ↑neoplasm) • …   Useful english dictionary

  • benign tumour — noun a tumor that is not cancerous • Syn: ↑benign tumor, ↑nonmalignant tumor, ↑nonmalignant tumour, ↑nonmalignant neoplasm • Hypernyms: ↑tumor, ↑tumour, ↑neoplasm …   Useful english dictionary

  • benign — be|nign [ bə naın ] adjective 1. ) a benign lump in your body or a benign disease is not cancer and will not kill you: a benign tumor ─ opposite MALIGNANT 2. ) FORMAL kind and nice: a benign smile a benign old gentleman ╾ be|nign|ly adverb …   Usage of the words and phrases in modern English


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.