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'''Neoplasia''' (''new growth'' in Greek) is the abnormal proliferation of cells in a [[biological tissue|tissue]] or [[organ (anatomy)|organ]], resulting in a '''neoplasm'''.
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[[Image:Colon cancer 2.jpg|thumb|200px|right|[[Colectomy]] specimen containing a malignant neoplasm, namely an invasive [[colorectal carcinoma]] (the crater-like, reddish, irregularly-shaped tumor)]]
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[[Image:Fibroids.jpg|thumb|200px|right|Diagram illustrating benign neoplasms, namely [[uterine fibroids|fibroids]] of the [[uterus]]]]
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'''Neoplasm''' (from [[ancient Greek]] νεο- ''neo-'', "new" + πλάσμα ''plasma'', "formation", "creation") is an abnormal mass of tissue as a result of '''neoplasia'''. Neoplasia is the abnormal [[cell proliferation|proliferation of cells]]. Prior to neoplasia, [[Cell (biology)|cell]]s often undergo an abnormal pattern of growth, such as [[metaplasia]] or [[dysplasia]].<ref name = "Abrams">{{cite web |last=Abrams |first=Gerald |title=Neoplasia I |url=http://open.umich.edu/education/med/m1/patientspop-genetics/fall2008/materials |accessdate=23 January 2012}}</ref> However, metaplasia or dysplasia do not always progress to neoplasia. The growth of neoplastic cells exceeds, and is not coordinated with, that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the stimuli. It usually causes a lump or [[tumor]]. Neoplasms may be [[Benign tumor|benign]], pre-malignant ([[carcinoma in situ]]) or malignant ([[cancer]]).
   
Some sources consider a neoplasm to be synonymous with a [[tumor]].<ref name="titlePancreas Cancer: Glossary of Terms">{{cite web |url=http://pathology.jhu.edu/pancreas/slides/glossary.html |title=Pancreas Cancer: Glossary of Terms |accessdate=2008-01-08 |format= |work=}}</ref>
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In modern medicine, the term ''tumor'' means a neoplasm that has formed a lump. In the past, the term ''tumor'' was used differently. Some neoplasms do not cause a lump.
   
Other sources make a distinction, stating that a neoplasm that forms a distinct mass is a [[tumor]].{{Fact|date=January 2008}} Other neoplasms, those that form no mass, include [[cervical intraepithelial neoplasia]], anal intraepithelial neoplasia, and [[leukemia]].
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==Classification==
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*[[International Classification of Diseases for Oncology]]
The structure of a neoplasm is less organized than that of the surrounding tissue.<ref name="titleWhat is neoplasm? Find the definition for neoplasm at WebMD">{{cite web |url=http://dictionary.webmd.com/terms/neoplasm.xml |title=What is neoplasm? Find the definition for neoplasm at WebMD |accessdate=2008-01-08 |format= |work=}}</ref>
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*[[WHO classification of the tumors of the central nervous system]]
   
 
==Types==
 
==Types==
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A neoplasm can be benign, potentially malignant (pre-cancer), or malignant ([[cancer]]).<ref name="titleCancer - Activity 1 - Glossary, page 4 of 5">{{cite web |url=http://science.education.nih.gov/supplements/nih1/cancer/other/glossary/act1-gloss4.htm |title=Cancer - Activity 1 - Glossary, page 4 of 5 |accessdate=2008-01-08 |format= |work=}}</ref>
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* [[Benign tumor|Benign neoplasm]]s include [[uterine fibroids]] and [[melanocytic nevus|melanocytic nevi]] (skin moles). They are circumscribed and localized and do not transform into cancer.<ref name = "Abrams" />
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* [[Malignant neoplasms]] are commonly called cancer. They invade and destroy the surrounding tissue, may form [[metastasis|metastases]] and eventually kill the host. Potentially malignant neoplasms include [[carcinoma in situ]]. They do not invade and destroy but, given enough time, will transform into a cancer.
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* [[Secondary neoplasm]] refers to any of a class of cancerous tumor that is either a metastatic offshoot of a primary tumor, or an apparently unrelated tumor that increases in frequency following certain cancer treatments such as [[chemotherapy]] or [[radiotherapy]].
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Of interest to psychoplogists are:
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* [[Brain neoplasms]]
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* [[Breast neoplasms]]
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* [[Endocrine neoplasms]]
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* [[Nervous system neoplasms]]
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==Difficulty of definition==
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Because neoplasia includes very different diseases, it is difficult to find an all-encompassing definition.<ref name="titleWhat is neoplasm">{{cite web |url=http://dictionary.webmd.com/terms/neoplasm.xml |title=What is neoplasm? Find the definition for neoplasm at WebMD |accessdate=2008-01-08 |format= |work=}}</ref> The definition of the British [[oncology|oncologist]] R.A. Willis is widely cited: "A neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues, and persists in the same excessive manner after cessation of the stimulus which evoked the change."<ref>Willis RA. ''The Spread of Tumors in the Human Body''. London, Butterworth & Co, 1952</ref> This definition is criticized because some neoplasms, such as nevi, are not progressive.
   
A neoplasm can be [[benign tumor|benign]], or potentially or frankly [[cancer|malignant]]. <ref name="titleCancer - Activity 1 - Glossary, page 4 of 5">{{cite web |url=http://science.education.nih.gov/supplements/nih1/cancer/other/glossary/act1-gloss4.htm |title=Cancer - Activity 1 - Glossary, page 4 of 5 |accessdate=2008-01-08 |format= |work=}}</ref>
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===Clonality===
* Benign neoplasms include [[leiomyoma]] (uterine fibroids) and [[Nevus|melanocytic nevi]] (moles).
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Neoplastic tumors often contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of neoplastic cells. These cells are presumed to be [[clone (cell biology)|clonal]] that is, they are descended from a single progenitor cell.
* Potentially malignant neoplasms include [[teratoma]]. Frankly (i.e., diagnosed) malignant neoplasms include many kinds of [[cancer]].
 
   
==Terminology==
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Sometimes, the neoplastic cells all carry the same [[mutation|genetic]] or [[epigenetics|epigenetic]] anomaly that becomes evidence for clonality. For lymphoid neoplasms, e.g. [[lymphoma]] and [[leukemia]], clonality is proven by the amplification of a single rearrangement of their [[immunoglobulin]] gene (for [[B cell]] lesions) or [[T-cell receptor]] gene (for [[T cell]] lesions). The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic.<ref name="pmid7990861">{{cite journal |author=Lee ES, Locker J, Nalesnik M, ''et al.'' |title=The association of Epstein-Barr virus with smooth-muscle tumors occurring after organ transplantation |journal=[[N. Engl. J. Med.]] |volume=332 |issue=1 |pages=19–25 |year=1995 |pmid=7990861 |doi= 10.1056/NEJM199501053320104|url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=7990861&promo=ONFLNS19}}</ref>
A neoplasm can be defined as an uncontrolled and [[Progressive illness|progressive]] growth.<ref>{{Dorlands|n_03|12561445}}</ref>
 
   
Other definitions are somtetimes used. The definition of the British oncologist R.A. Willis is widely cited:
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It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. Therefore, clonality is not required in the definition of neoplasia.
{{cquote|A neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues, and persists in the same excessive manner after cessation of the stimulus which evoked the change.<ref>Willis RA: The Spread of Tumors in the Human Body. London, Butterworth & Co, 1952</ref>}}
 
   
==Genetics==
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==Neoplasia vs. tumor==
Neoplastic tumors often contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of ''neoplastic cells.'' These cells are ''clonal'' - that is, they are descended from a single progenitor cell.
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[[Tumor]] (Latin for ''swelling'', one of the cardinal signs of inflammation) originally meant any form of [[Swelling (medical)|swelling]], neoplastic or not. Current English, however, both medical and non-medical, uses ''tumor'' as a synonym of ''neoplasm''.<ref name="titlePancreas Cancer: Glossary of Terms">{{cite web |url=http://pathology.jhu.edu/pancreas/slides/glossary.html |title=Pancreas Cancer: Glossary of Terms |accessdate=2008-01-08 |format= |work=}}
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</ref>
   
The neoplastic cells typically bear common [[mutation|genetic]] or [[epigenetics|epigenetic]] abnormalities which are not seen in the non-neoplastic [[stromal cell]]s and [[endothelium|blood-vessel forming cells]], whose growth is dependent on molecular stimuli from the neoplastic cells.
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Some neoplasms do not form a tumor. These include [[leukemia]] and most forms of [[carcinoma in situ]].
   
The demonstration of clonality is now considered by many to be necessary (though not sufficient) to define a cellular proliferation as neoplastic.<ref name="pmid7990861">{{cite journal |author=Lee ES, Locker J, Nalesnik M, ''et al'' |title=The association of Epstein-Barr virus with smooth-muscle tumors occurring after organ transplantation |journal=[[N. Engl. J. Med.]] |volume=332 |issue=1 |pages=19–25 |year=1995 |pmid=7990861 |doi= |url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=7990861&promo=ONFLNS19}}</ref>
 
   
 
==See also==
 
==See also==

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Neoplasms
ICD-10 C00-D48
ICD-9 140-239.99
OMIM [1]
DiseasesDB 28841
MedlinePlus 001310.
eMedicine /
MeSH {{{MeshNumber}}}



File:Colon cancer 2.jpg
File:Fibroids.jpg

Neoplasm (from ancient Greek νεο- neo-, "new" + πλάσμα plasma, "formation", "creation") is an abnormal mass of tissue as a result of neoplasia. Neoplasia is the abnormal proliferation of cells. Prior to neoplasia, cells often undergo an abnormal pattern of growth, such as metaplasia or dysplasia.[1] However, metaplasia or dysplasia do not always progress to neoplasia. The growth of neoplastic cells exceeds, and is not coordinated with, that of the normal tissues around it. The growth persists in the same excessive manner even after cessation of the stimuli. It usually causes a lump or tumor. Neoplasms may be benign, pre-malignant (carcinoma in situ) or malignant (cancer).

In modern medicine, the term tumor means a neoplasm that has formed a lump. In the past, the term tumor was used differently. Some neoplasms do not cause a lump.

Classification

Types

A neoplasm can be benign, potentially malignant (pre-cancer), or malignant (cancer).[2]

  • Benign neoplasms include uterine fibroids and melanocytic nevi (skin moles). They are circumscribed and localized and do not transform into cancer.[1]
  • Malignant neoplasms are commonly called cancer. They invade and destroy the surrounding tissue, may form metastases and eventually kill the host. Potentially malignant neoplasms include carcinoma in situ. They do not invade and destroy but, given enough time, will transform into a cancer.
  • Secondary neoplasm refers to any of a class of cancerous tumor that is either a metastatic offshoot of a primary tumor, or an apparently unrelated tumor that increases in frequency following certain cancer treatments such as chemotherapy or radiotherapy.

Of interest to psychoplogists are:


Difficulty of definition

Because neoplasia includes very different diseases, it is difficult to find an all-encompassing definition.[3] The definition of the British oncologist R.A. Willis is widely cited: "A neoplasm is an abnormal mass of tissue, the growth of which exceeds and is uncoordinated with that of the normal tissues, and persists in the same excessive manner after cessation of the stimulus which evoked the change."[4] This definition is criticized because some neoplasms, such as nevi, are not progressive.

Clonality

Neoplastic tumors often contain more than one type of cell, but their initiation and continued growth is usually dependent on a single population of neoplastic cells. These cells are presumed to be clonal – that is, they are descended from a single progenitor cell.

Sometimes, the neoplastic cells all carry the same genetic or epigenetic anomaly that becomes evidence for clonality. For lymphoid neoplasms, e.g. lymphoma and leukemia, clonality is proven by the amplification of a single rearrangement of their immunoglobulin gene (for B cell lesions) or T-cell receptor gene (for T cell lesions). The demonstration of clonality is now considered to be necessary to identify a lymphoid cell proliferation as neoplastic.[5]

It is tempting to define neoplasms as clonal cellular proliferations but the demonstration of clonality is not always possible. Therefore, clonality is not required in the definition of neoplasia.

Neoplasia vs. tumor

Tumor (Latin for swelling, one of the cardinal signs of inflammation) originally meant any form of swelling, neoplastic or not. Current English, however, both medical and non-medical, uses tumor as a synonym of neoplasm.[6]

Some neoplasms do not form a tumor. These include leukemia and most forms of carcinoma in situ.


See also


Template:Endocrine gland neoplasia

References

  1. 1.0 1.1 Abrams, Gerald Neoplasia I. URL accessed on 23 January 2012.
  2. Cancer - Activity 1 - Glossary, page 4 of 5. URL accessed on 2008-01-08.
  3. What is neoplasm? Find the definition for neoplasm at WebMD. URL accessed on 2008-01-08.
  4. Willis RA. The Spread of Tumors in the Human Body. London, Butterworth & Co, 1952
  5. Lee ES, Locker J, Nalesnik M, et al. (1995). The association of Epstein-Barr virus with smooth-muscle tumors occurring after organ transplantation. N. Engl. J. Med. 332 (1): 19–25.
  6. Pancreas Cancer: Glossary of Terms. URL accessed on 2008-01-08.


Template:Endocrine gland neoplasia Template:Epithelial neoplasms Template:Digestive system neoplasia Template:Respiratory and intrathoracic neoplasia


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