View source for Neoplasm

{{Infobox_Disease
 | Name           = Neoplasm
 | Image          = Colon cancer 2.jpg
 | Caption        = [[Colectomy]] specimen containing a '''malignant neoplasm''', namely an invasive [[colorectal carcinoma]] (the crater-like, reddish, irregularly-shaped tumor).
 | DiseasesDB     = 28841
 | ICD10          = {{ICD10|C|00||c|00}}-{{ICD10|D|48||d|37}}
 | ICD9           = {{ICD9|140}}-{{ICD9|239.99}}
 | ICDO           = 
 | OMIM           = 
 | MedlinePlus    = 001310.
 | eMedicineSubj  = 
 | eMedicineTopic = 
 | MeshID         = D009369
}}
{{SI}}
{{CMG}}



==Overview==
[[Image:Fibroids.jpg|thumb|200px|left|Diagram illustrating '''benign neoplasms''', namely [[uterine fibroids|fibroids]] of the [[uterus]].]]
'''Neoplasia''' (''new growth'' in Greek) is the abnormal proliferation of [[Cell (biology)|cells]], resulting in a '''neoplasm'''. <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> <ref>{{Dorlands|n_03|12561445}}</ref> Neoplasia is the scientific term for the group of diseases commonly called '''[[tumor]]''' or '''[[cancer]]'''. <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>

Because neoplasia includes very different diseases, it is difficult to find a definition that describe them all. The definition of the British oncologist R.A. Willis is widely cited:

{{quotation|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>}}

==Types==
A neoplasm can be [[benign tumor|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>
* Benign neoplasms include [[uterine fibroids]] and [[Nevus|melanocytic nevi]] (skin moles). They do not transform into [[cancer]].
* Potentially malignant neoplasms include [[carcinoma in situ]]. They do not invade and destroy but, given enough time, will transform into a [[cancer]]. 
* Malignant neoplasms are commonly called [[cancer]]. They invade and destroy the surrounding tissue,  may form [[metastasis|metastases]] and eventually kill the host.

==Difficulty of definition==
A precise and all-encompassing definition of neoplasm has proven elusive.  A neoplasm has been defined as an uncontrolled and [[Progressive illness|progressive]] growth, although this definition is criticized because some neoplasms, such as nevi, are not progressive.<ref>{{Dorlands|n_03|12561445}}</ref>

Some sources consider a neoplasm to be synonymous with a [[tumor]] or unusual mass of tissue.<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>  This is criticized because many neoplasms form no mass, including [[cervical intraepithelial neoplasia]], anal intraepithelial neoplasia, and [[leukemia]].

==Biological properties of neoplastic cells==
The structure of a neoplasm is less organized than that of the surrounding tissue.<ref name="titleWhat is neoplasm?">{{cite web |url=http://dictionary.webmd.com/terms/neoplasm.xml |title=What is neoplasm? |accessdate=2008-01-08 |format= |work=}}</ref>

===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 usually presumed to be ''[[clone (cell biology)|clonal]]'' - that is, they are descended from a single progenitor cell. 

The neoplastic cells typically bear common [[mutation|genetic]] or [[epigenetics|epigenetic]] abnormalities, an evidence of clonality. For some types of neoplasm, e.g. [[lymphoma]] and [[leukemia]], the demonstration of clonality is now considered 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= 10.1056/NEJM199501053320104|url=http://content.nejm.org/cgi/pmidlookup?view=short&pmid=7990861&promo=ONFLNS19}}</ref>

==See also==
*[[Cancer]]
*[[Tumor]]
*[[Benign tumor]]
*[[Dysplasia]]
*[[Hyperplasia]]
*[[Oncology]]
*[[Oncogene]]

==References==
{{reflist}}

{{Tumors}}
{{pathology}}

[[Category:Types of cancer]]
[[Category:Oncology]]
[[Category:pathology]]

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