Editing Neoplasm (section)

==Types==
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A neoplasm can be [[benign tumor|benign]], potentially malignant, 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 |access-date=2008-01-08 |url-status=dead |archive-url=https://web.archive.org/web/20080509064024/http://science.education.nih.gov/supplements/nih1/cancer/other/glossary/act1-gloss4.htm |archive-date=2008-05-09 }}</ref>
* [[Benign tumor]]s include [[uterine fibroids]], [[osteophytes]], and [[melanocytic nevus|melanocytic nevi]] (skin moles). They are circumscribed and localized and do not transform into cancer.<ref name = "Abrams" />
* Potentially-malignant neoplasms include [[carcinoma in situ]]. They are localised, and do not invade and destroy but in time, may transform into cancer.
* Malignant neoplasms are commonly called cancer. They invade and destroy the surrounding tissue, may form [[metastasis|metastases]] and, if untreated or unresponsive to treatment, will generally prove fatal.
* 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]].
* Rarely there can be a metastatic neoplasm with no known site of the primary cancer and this is classed as a [[cancer of unknown primary origin]].

===Clonality===
Neoplastic tumors are often [[Tumour heterogeneity|heterogeneous]] and contain more than one type of cell, but their initiation and continued growth are usually dependent on a single population of neoplastic cells. These cells are presumed to be [[Monoclonality|monoclonal]] – that is, they are derived from the same cell,<ref>{{Cite web|url=http://www.medterms.com/script/main/art.asp?articlekey=2754|title=Medical Definition of Clone|access-date=2015-02-10|archive-date=2012-10-25|archive-url=https://web.archive.org/web/20121025074001/http://www.medterms.com/script/main/art.asp?articlekey=2754|url-status=dead}}</ref> and all carry the same [[mutation|genetic]] or [[epigenetics|epigenetic]] anomaly – evident of 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 |vauthors=Lee ES, Locker J, Nalesnik M, Reyes J, Jaffe R, Alashari M, Nour B, Tzakis A, Dickman PS | 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 |date=January 1995 | pmid = 7990861 | doi = 10.1056/NEJM199501053320104 | doi-access = free }}</ref>

===Neoplasm vs. tumor===
The word ''tumor'' or ''tumour'' comes from the Latin word for ''swelling'', which is one of the cardinal signs of inflammation. The word originally referred to any form of [[Swelling (medical)|swelling]], neoplastic or not. In modern English, ''tumor (non-US spelling: tumour)''  is 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.<ref name="titlePancreas Cancer: Glossary of Terms">{{cite web |url=http://pathology.jhu.edu/pancreas/slides/glossary.html |title=Pancreas Cancer: Glossary of Terms |access-date=2008-01-08 |archive-date=2010-06-05 |archive-url=https://web.archive.org/web/20100605173602/http://pathology.jhu.edu/pancreas/slides/glossary.html |url-status=dead }}</ref><ref>{{cite encyclopedia |encyclopedia=Dorland's Illustrated Medical Dictionary |title=Tumor |edition=31st|year=2007 |publisher=[[Saunders (publisher)|Saunders]] |isbn=978-1-84972-348-0}}</ref> Some neoplasms do not form a tumor; these include [[leukemia]] and most forms of [[carcinoma in situ]]. ''Tumor'' is also not synonymous with ''[[cancer]].'' While cancer is by definition malignant, a tumor can be [[Benign tumor|benign]], [[precancerous condition|precancerous]], or [[Malignancy|malignant]].{{cn|date=May 2023}}

The terms ''mass'' and ''nodule'' are often used synonymously with ''tumor''. Generally speaking, however, the term ''tumor'' is used generically, without reference to the physical size of the lesion.<ref name="ReferenceA"/> More specifically, the term ''mass'' is often used when the lesion has a maximal diameter of at least 20 millimeters (mm) in the greatest direction, while the term ''[[Nodule (medicine)|nodule]]'' is usually used when the size of the lesion is less than 20&nbsp;mm in its greatest dimension (25.4&nbsp;mm = 1&nbsp;inch).<ref name="ReferenceA"/>