Tumor

Tumor

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A tumor or tumour is commonly used as a synonym for a neoplasm (a solid or fluid-filled (cystic) lesion that may or may not be formed by an abnormal growth of neoplastic cells) that appears enlarged in size. Tumor is not synonymous with cancer
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...

. While cancer is by definition malignant, a tumor can be benign, pre-malignant, or malignant
Malignant
Malignancy is the tendency of a medical condition, especially tumors, to become progressively worse and to potentially result in death. Malignancy in cancers is characterized by anaplasia, invasiveness, and metastasis...

, or can represent a lesion with no cancerous potential whatsoever.

Etymology


The term tumour/tumor is derived from the Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 word for "swelling" -- tumor. It is similar to the Old French
Old French
Old French was the Romance dialect continuum spoken in territories that span roughly the northern half of modern France and parts of modern Belgium and Switzerland from the 9th century to the 14th century...

 tumour (contemporary French: tumeur). In the Commonwealth the spelling "tumour" is commonly used, whereas in the U.S. it is usually spelled "tumor".

In its medical sense it has traditionally meant an abnormal swelling of the flesh. The Roman medical encyclopedist Celsus
Aulus Cornelius Celsus
Aulus Cornelius Celsus was a Roman encyclopedist, known for his extant medical work, De Medicina, which is believed to be the only surviving section of a much larger encyclopedia. The De Medicina is a primary source on diet, pharmacy, surgery and related fields, and it is one of the best sources...

 (ca 30 BC–38 AD) described the four cardinal signs of acute inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 as tumor, dolor
Pain
Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

, calor
Calor
Calor Gas is a brand of bottled butane and propane which is available in Britain and Ireland. It comes in cylinders, which have a special gas regulator.Calor was formed in 1935. Calor is the UK's leading supplier of Liquefied petroleum gas...

, and rubor (swelling, pain, increased heat, and redness). His treatise, De Medicina
De Medicina
De Medicina is a 1st-century medical treatise by Aulus Cornelius Celsus, a Roman encyclopedist and possibly a practicing physician. It is the only surviving section of a much larger encyclopedia; only small parts still survive from sections on agriculture, military science, oratory, jurisprudence...

, was the first medical book printed in 1478 following the invention of the printing press.

In contemporary English, the word tumor is often used as a synonym for a cystic (liquid-filled) growth or solid neoplasm (cancerous or non-cancerous), with other forms of swelling often referred to merely as swellings
Swelling (medical)
In medical parlance, swelling is the transient enlargement or protuberance in the body and may include tumors. According to cause, it may be congenital, traumatic, inflammatory, neoplastic or miscellaneous....

.

Related terms are common in the medical literature, where the nouns tumefaction and tumescence
Tumescence
Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood of the erectile tissues, marking sexual excitation and possible readiness for sexual activity...

 (derived from the adjective tumefied), are current medical terms for non-neoplastic swelling. This type of swelling is most often caused by inflammation
Inflammation
Inflammation is part of the complex biological response of vascular tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process...

 caused by trauma, infection, and other factors..etc.

Tumors may be caused by conditions other than an overgrowth of neoplastic cells, however. Cysts (such as sebaceous cysts) are also referred to as tumors, even though they have no neoplastic cells. This is standard in medical billing terminology (especially when billing for a growth whose pathology has yet to be determined).

Causes


A neoplasm can be caused an abnormal proliferation of tissues, which can be caused by genetic mutation
Mutation
In molecular biology and genetics, mutations are changes in a genomic sequence: the DNA sequence of a cell's genome or the DNA or RNA sequence of a virus. They can be defined as sudden and spontaneous changes in the cell. Mutations are caused by radiation, viruses, transposons and mutagenic...

s. Not all types of neoplasms cause a tumorous overgrowth of tissue, however (such as leukemia
Leukemia
Leukemia or leukaemia is a type of cancer of the blood or bone marrow characterized by an abnormal increase of immature white blood cells called "blasts". Leukemia is a broad term covering a spectrum of diseases...

 or carcinoma in situ
Carcinoma in situ
Carcinoma in situ is an early form of cancer that is defined by the absence of invasion of tumor cells into the surrounding tissue, usually before penetration through the basement membrane. In other words, the neoplastic cells proliferate in their normal habitat, hence the name "in situ"...

).

Benign conditions that are not associated with an abnormal proliferation of tissue (such as sebaceous cysts) can also present as tumors, however, but have no malignant potential. Breast cyst
Breast cyst
A breast cyst is a fluid-filled sac within the breast. One can have one or more breast cysts. They're often described as round or oval lumps with distinct edges. In texture, a breast cyst usually feels like a soft grape or a water-filled balloon, but sometimes a breast cyst feels firm.Breast cysts...

s (as occur commonly during pregnancy and at other times) are another example, as are other encapsulated glandular swellings (thyroid, adrenal gland, pancreas).

Encapsulated hematomas, encapsulated necrotic tissue (from an insect bite, foreign body, or other noxious mechanism), and keloids and granulomas (discrete overgrowths of scar tissue) may also present as tumors.

Discrete localized enlargements of normal structures (ureters, blood vessels, intrahepatic or extrahepatic biliary ducts, pulmonary inclusions, or gastrointestinal duplications) due to outflow obstructions or narrowings, or abnormal connections, may also present as a tumor. Examples are arteriovenous fistulae or aneurysms (with or without thrombosis), biliary fistulae or aneurysms, sclerosing cholangitis, cysticercosis or hydatid cysts, intestinal duplications, and pulmonary inclusions as seen with cystic fibrosis. It can be dangerous to biopsy a number of types of tumor in which the leakage of their contents would potentially be catastrophic. When such types of tumors are encountered, diagnostic modalities such as ultrasound, CT scans, MRI, angiograms, and nuclear medicine scans are employed prior to (or during) biopsy and/or surgical exploration/excision in an attempt to avoid such severe complications.

The nature of a tumor is determined by imaging, by surgical exploration, and/or by a pathologist
Anatomical pathology
Anatomical pathology or Anatomic pathology is a medical specialty that is concerned with the diagnosis of disease based on the gross, microscopic, chemical, immunologic and molecular examination of organs, tissues, and whole bodies...

 after examination of the tissue from a biopsy
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...

 or a surgical specimen
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...

.

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