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Tumor

Tumor

A tumor is an abnormal growth of tissue. Also known as a neoplasm (meaning "new formation"), a tumor can be either benign (not serious or harmful) or malignant (cancerous or deadly). Either type may require therapy to remove it or reduce its size.

It is not known what triggers a tumor's abnormal growth. The body normally creates cells only at a rate needed to replace those that die or to aid an individual's growth and development. The growth of a tumor, however, is unregulated by normal body control mechanisms.

Benign and malignant tumors

A benign tumor is a well-defined growth with smooth boundaries that simply grows in diameter. This can be harmful if the tumor compresses the surrounding tissue against a hard surface in the body. A benign brain tumor that compresses brain tissue against the skull or the bony floor of the cranium can result in paralysis, loss of hearing or sight, dizziness, and other ailments. A tumor growing in the abdomen can compress the intestine and interfere with digestion. It also can prevent the proper functioning of the liver or pancreas. The benign tumor usually grows at a relatively slow pace and may stop growing for a time when it reaches a certain size.

Words to Know

Benign: A slow-growing, self-contained tumor that is not seriously harmful.

Biopsy: The surgical removal of a small part of a tumor, which is then studied under a microscope to determine whether it is benign or malignant.

Chemotherapy: Use of powerful chemicals to kill cancer cells in the human body.

Malignant: A usually fast-growing, often fatal tumor that invades surrounding tissue and sheds cells that spread throughout the body, creating new tumors.

Metastasis: Spreading of a cancerous growth by shedding cells that grow in other locations.

Radiation therapy: Use of radioactive substances to kill cancer cells in the human body.

A malignant tumor may grow quite rapidly and can be fatal. It usually has irregular boundaries and invades the surrounding tissue instead of pressing it aside. Most important, this cancer also sheds cells that travel through the bloodstream, starting new tumor growth at other locations in the body. This process is called metastasis (pronounced me-TAS-ta-sis). The cancerous cells can establish a cancer in tissue that is different from the original cancer. A breast cancer could spread to bone tissue or to liver tissue.

Medical approaches

Benign tissue is distinctly different from cancer tissue. However, it is difficult to determine whether a tumor is benign or malignant without surgically removing a sample of it and studying the tissue under the microscope. This sampling is called a biopsy (pronounced BY-op-see).

A benign tumor can be removed surgically if it is in a location that a surgeon can reach. A tumor growing in an unreachable area of the body can be treated using radiation (by which the patient is administered radioactive substances that target a specific area and destroy cells there). Another method is to insert thin probes into the tumor and freeze it with liquid nitrogen. This operation is called cryosurgery (pronounced cry-o-SUR-jer-ee).

A malignant tumor may be removed surgically. However, if the tumor has been growing for some time and has begun to metastasize or spread, the patient also may require treatment with powerful chemicals

to kill any stray cells. This treatment is called chemotherapy (pronounced key-moe-THER-a-pee).

[See also Cancer ]

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Tumor

Tumor

What Is a Tumor?

Who Gets Tumors?

How Are Tumors Diagnosed and Treated?

Resource

A tumor (Too-mor) is an abnormal growth of new tissue that can occur in any of the bodys organs. Many people automatically associate tumors with the disease called cancer*, but that is not always the case.

* cancer
is any tumorous (TOO-mor-us) condition, the natural (untreated) course of which is fatal.

KEYWORDS

for searching the Internet and other reference sources

Cancer

Neoplasm

What Is a Tumor?

The human body is made up of many types of cells that are constantly dividing to produce new, younger cells that can take over for aging or damaged cells. Through this process, the body heals its injuries and keeps tissues healthy. Sometimes, this process gets out of control, and new cells continue to be produced even when they are not needed, forming a clump of extra tissue, a tumor.

There are two types of tumors:

  • malignant (ma-LIG-nant), or cancerous, tumors are made up of abnormally shaped cells that grow quickly, invade nearby healthy tissues, and often make their way into the bloodstream. When these cells travel to other parts of the body, they form additional tumors.
  • Benign (be-NINE) tumors are not cancer. They grow slowly and are self-contained; that is, they do not invade and destroy the tissue around them, nor do they spread to other parts of the body. Their cells are usually normally shaped.

Who Gets Tumors?

People of all ages can develop tumors, but generally they are more common as people grow older. Researchers believe that malignant tumors result from a combination of causes, the most important being genetic and environmental. People may inherit a tendency to develop certain kinds of tumors from their parents. Also, repeated exposure to harmful substances such as cigarette smoke, pollutants, and too much sunlight can damage cells and trigger the process of tumor formation.

When a tumor first starts to develop, it is so small that it does not cause symptoms. As it grows, it usually causes symptoms that vary according to its location. For instance, a tumor in the lung may cause a feeling of irritation or a nagging cough. People with brain tumors may experience headaches, dizziness, blurry vision, or lack of coordination. A person with a tumor in the colon* may notice that going to the bathroom is painful or produces blood.

* colon
is part of the large intestine where waste is formed and moved to the rectum, which stores it until it passes out of the body.

How Are Tumors Diagnosed and Treated?

A doctor can usually diagnose a tumor with one of many tests that create images of the inside of the body, such as x-rays, ultrasound*, CT scans*, or MRI*. The next step is to figure out whether the tumor is benign or malignant through a process called biopsy (BY-op-see). Surgeons remove part or all of the tumor and examine a sample under the microscope. The appearance of the cells will indicate whether a tumor is cancerous or not.

* ultrasound
is a painless procedure in which sound waves passing through the body create images on a computer screen.
* CT scans
or CAT scans are the shortened names for computerized axial tomography (to-MOG-ra-fee), which uses computers to view structures inside the body.
* MRI,
which is short for magnetic resonance imaging, produces computerized images of internal body tissues based on the magnetic properties of atoms within the body.

Even though a benign tumor is not harmful, it may have to be removed if it causes pain, pressure, or other symptoms. In many cases of a malignancy, the tumor and any affected surrounding tissue will be removed. Sometimes, radiation therapy (directed high-energy x-rays) or chemotherapy (cancer-fighting drugs) may be used to shrink the tumor.

See also

Cancer

Tobacco-Related Diseases

Resource

The National Cancer Institute, part of the U.S. National Institutes of Health (NIH), has a fact sheet, What You Need to Know about Cancer, and a book, When Someone in Your Family Has Cancer, available by phone or on its website at the pages given below. For the latter, from the Publication Index, follow the link Living with Cancer/Supporting People with Cancer. Telephone 800-422-6237 http://cancernet.nci.nih.gov/wyntk_pubs/cancer.htm http://rex.nci.nih.gov/NCI_PUB_INDEX/PUB_INDEX_DOC.html

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"Tumor." Complete Human Diseases and Conditions. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/tumor

tumour

tumour Any abnormal growth in or on the body, arising from some particular tissue or cell type. A tumour may be harmless (benign), remaining at its site of origin and becoming a problem only cosmetically or by its size; or cancerous (malignant), invading surrounding tissues, and seeding elsewhere (metastasizing) via the lymphatic or blood vessels. The technical term for a tumour of whatever varity is ‘neoplasm’.

Stuart Judge


See cancer.

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"tumour." The Oxford Companion to the Body. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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"tumour." The Oxford Companion to the Body. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/medicine/encyclopedias-almanacs-transcripts-and-maps/tumour

tumour

tumour An abnormal growth of new tissue that occurs anywhere in the body. Such a growth may be harmless or benign (e.g. a wart). Alternatively it may be malignant, destroying the tissue upon which it grows. It may also invade other tissues through the process of metastasis, in which cells sloughed off from the tumour are carried to other parts of the body. See also CANCER CELL.

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"tumour." A Dictionary of Zoology. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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"tumour." A Dictionary of Zoology. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/science/dictionaries-thesauruses-pictures-and-press-releases/tumour

tumor

tu·mor / ˈt(y)oōmər/ (Brit. tu·mour) • n. a swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissue, whether benign or malignant. ∎ archaic a swelling of any kind. DERIVATIVES: tu·mor·ous / -mərəs/ adj.

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"tumor." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

"tumor." The Oxford Pocket Dictionary of Current English. . Encyclopedia.com. (August 19, 2017). http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/tumor-0

"tumor." The Oxford Pocket Dictionary of Current English. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/humanities/dictionaries-thesauruses-pictures-and-press-releases/tumor-0

tumour

tumour (tew-mer) n. any abnormal swelling in or on a part of the body. The term is usually applied to an abnormal growth of tissue, which may be benign or malignant. Compare cyst.

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"tumour." A Dictionary of Nursing. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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"tumour." A Dictionary of Nursing. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/tumour

tumour

tumour Any uncontrolled, abnormal proliferation of cells, often leading to the formation of a lump. Tumours are classified as either benign (non-cancerous) or malignant.

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"tumour." World Encyclopedia. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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tumor

tumor (tew-mer) n. swelling: one of the four classical signs of inflammation in a tissue. See also calor, dolor, rubor.

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"tumor." A Dictionary of Nursing. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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"tumor." A Dictionary of Nursing. . Retrieved August 19, 2017 from Encyclopedia.com: http://www.encyclopedia.com/caregiving/dictionaries-thesauruses-pictures-and-press-releases/tumor

tumor

tumor: see neoplasm.

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"tumor." The Columbia Encyclopedia, 6th ed.. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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tumour

tumour See neoplasm.

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"tumour." A Dictionary of Biology. . Encyclopedia.com. 19 Aug. 2017 <http://www.encyclopedia.com>.

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tumor

tumordormer, former, korma, Norma, performer, pro-forma, stormer, transformer, trauma, warmer •sixth-former • barnstormer •aroma, carcinoma, chroma, coma, comber, diploma, glaucoma, Homer, lymphoma, melanoma, misnomer, Oklahoma, Omagh, roamer, Roma, romer, sarcoma, soma •beachcomber •bloomer, boomer, consumer, Duma, humour (US humor), Nkrumah, perfumer, puma, roomer, rumour (US rumor), satsuma, stumer, Sumer, tumour (US tumor) •zeugma • fulmar •bummer, comer, drummer, hummer, midsummer, mummer, plumber, rummer, strummer, summa, summer •latecomer • newcomer • agama •welcomer •astronomer, monomer •ashrama • isomer • gossamer •customer •affirmer, Burma, derma, Irma, murmur, squirmer, terra firma, wormer

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tumour

tumourdormer, former, korma, Norma, performer, pro-forma, stormer, transformer, trauma, warmer •sixth-former • barnstormer •aroma, carcinoma, chroma, coma, comber, diploma, glaucoma, Homer, lymphoma, melanoma, misnomer, Oklahoma, Omagh, roamer, Roma, romer, sarcoma, soma •beachcomber •bloomer, boomer, consumer, Duma, humour (US humor), Nkrumah, perfumer, puma, roomer, rumour (US rumor), satsuma, stumer, Sumer, tumour (US tumor) •zeugma • fulmar •bummer, comer, drummer, hummer, midsummer, mummer, plumber, rummer, strummer, summa, summer •latecomer • newcomer • agama •welcomer •astronomer, monomer •ashrama • isomer • gossamer •customer •affirmer, Burma, derma, Irma, murmur, squirmer, terra firma, wormer

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