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tumour

 
Britannica Concise Encyclopedia: tumour
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Mass of abnormal tissue that arises from normal cells, has no useful function, and tends to grow. Cell abnormalities may include increased size or number or loss of characteristics that differentiate their tissue of origin. Cells in malignant tumours (see cancer) have a distorted size, shape, and/or structure. Less differentiated cells tend to grow faster. Malignant tumours invade tissues locally and spread (metastasize) in blood or lymph: the stronger the tendency to metastasize, the more malignant the tumour. Tumours may not cause pain until they press on or invade nerves. Both benign and malignant tumours can press on nearby structures, block vessels, or produce excess hormones, all of which can cause death. Benign tumours remain as a solid mass that can be removed by surgery if accessible; they can consist of various tissues and may become malignant; malignant tumours, though they may remain quiescent for a time, never become benign.

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World of the Body: tumour
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Home > Library > Health > World of the Body

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.

Sports Science and Medicine: tumour
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Home > Library > Health > Sports Science and Medicine

An abnormal swelling due to the growth of cells. Tumours maybe benign or malignant.

 
 

 

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Britannica Concise Encyclopedia. Britannica Concise Encyclopedia. © 2006 Encyclopædia Britannica, Inc. All rights reserved.  Read more
World of the Body. The Oxford Companion to the Body. Copyright © 2001, 2003 by Oxford University Press. All rights reserved.  Read more
Sports Science and Medicine. The Oxford Dictionary of Sports Science & Medicine. Copyright © Michael Kent 1998, 2006, 2007. All rights reserved.  Read more