{{Short description|Pre-cancerous abnormal growth of tissue}} {{DISPLAYTITLE:Carcinoma ''in situ''}}{{Infobox medical condition (new) | name = Carcinoma ''in situ'' | synonyms = ''in situ'' neoplasm | image = In situ carcinoma-en.svg | caption =
| pronounce = | field = Oncology | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }} '''Carcinoma ''in situ''''' ('''CIS''') is a group of abnormal cells.<ref name=Chang2007/><ref>{{cite web|title=II Neoplams|url=http://apps.who.int/classifications/icd10/browse/2010/en|website=World Health Organization|access-date=19 June 2014}}</ref> While they are a form of neoplasm,<ref>{{cite book | author = World Health Organization |title=International statistical classification of diseases and related health problems|date=2004|publisher=World Health Organization|location=Geneva|isbn=9789241546492|page=38|edition=10. rev., 2.|url=https://books.google.com/books?id=3Ylb6Qw8PVEC&pg=PA38}}</ref> there is disagreement over whether CIS should be classified as cancer. This controversy also depends on the exact CIS in question (e.g., cervical, skin, breast). Some authors do not classify them as cancer, however, recognizing that they can potentially become cancer.<ref name=Chang2007>{{cite book| vauthors = Chang A |title=Oncology: An Evidence-Based Approach|date=2007|publisher=Springer|isbn=978-0-387-31056-5 |page=162|url=https://books.google.com/books?id=vxh6u1-ETk0C&pg=PA162}}</ref> Others classify certain types as a non-invasive form of cancer.<ref>{{cite book| vauthors = Myers JA, Millikan KW, Saclarides TJ |title=Common surgical diseases an algorithmic approach to problem solving.|date=2008|publisher=Springer|location=New York|isbn=978-0-387-75246-4 |edition=2nd rev.|url=https://books.google.com/books?id=ysPs3kwe0h0C&pg=PA347}}</ref><ref>{{cite journal | vauthors = Allred DC | title = Ductal carcinoma in situ: terminology, classification, and natural history | journal = Journal of the National Cancer Institute. Monographs | volume = 2010 | issue = 41 | pages = 134–138 | date = 2010 | pmid = 20956817 | pmc = 5161057 | doi = 10.1093/jncimonographs/lgq035 }}</ref> U.S. surgical pathologist Albert C. Broders introduced both the term and concept of carcinoma ''in situ'' in 1932.<ref name="Wright">{{cite journal |last=Wright |first=James R. Jr. |title=Albert C. Broders' paradigm shifts involving the prognostication and definition of cancer |journal=Archives of Pathology & Laboratory Medicine |date=2012 |volume=136 |issue=11 |pages=1437–1446 |doi=10.5858/arpa.2011-0567-HP |pmid=23106590 }}</ref><ref name="cis">{{Cite OED|carcinoma in situ|1023159588}}</ref> The term "pre-cancer" has also been used.
These abnormal cells grow in their normal place, thus ''in situ'' ({{langnf|la||term1=in its place}}). For example, carcinoma ''in situ'' of the skin, also called Bowen's disease, is the accumulation of dysplastic epidermal cells within the epidermis only, that has failed to penetrate into the deeper dermis. For this reason, CIS will usually not form a tumor. Rather, the lesion is flat (in the skin, cervix, etc.) or follows the existing architecture of the organ (in the breast, lung, etc.). Exceptions include CIS of the colon (polyps), the bladder (preinvasive papillary cancer), or the breast (ductal carcinoma ''in situ'' or lobular carcinoma ''in situ'').
Many forms of CIS have a high probability of progression into cancer,<ref>Ridge JA, Glisson BS, Lango MN, et al. [http://www.cancernetwork.com/cancer-management-11/chapter04/article/10165/1402663 "Head and Neck Tumors"] {{Webarchive|url=https://web.archive.org/web/20090720201346/http://www.cancernetwork.com/cancer-management-11/chapter04/article/10165/1402663 |date=2009-07-20 }} in Pazdur R, Wagman LD, Camphausen KA, Hoskins WJ (Eds) [http://www.cancernetwork.com/cancer-management-11/ Cancer Management: A Multidisciplinary Approach] {{Webarchive|url=https://web.archive.org/web/20131004224102/http://www.cancernetwork.com/cancer-management-11/ |date=2013-10-04 }}. 11 ed. 2008.</ref> and therefore removal may be recommended; however, progression of CIS is known to be highly variable and not all CIS becomes invasive cancer.
In the TNM classification, carcinoma ''in situ'' is reported as TisN0M0 (stage 0).<ref>{{cite web |url=http://www.cancer.gov/cancertopics/factsheet/Detection/staging |title=Cancer Staging Fact Sheet |publisher=National Cancer Institute |access-date=June 24, 2014}}</ref>
==Terminology== These terms are related since they represent the steps of the progression toward cancer: *Dysplasia is the earliest form of precancerous lesion recognizable in a biopsy. Dysplasia can be low-grade or high-grade. High-grade dysplasia may also be referred to as carcinoma ''in situ''. *Invasive carcinoma, usually simply called cancer, has the potential to invade and spread to surrounding tissues and structures, and may eventually be lethal.
==Examples== thumb|High-grade dysplasia (carcinoma ''in situ'') in the uterine cervix: The abnormal epithelium is extending into a mucous gland to the left of center. This disease can progress to invasive cancer (squamous cell carcinoma) of the cervix. * Cervical squamous intraepithelial lesion (SIL), previously called cervical intraepithelial neoplasia (CIN), is a form of dysplasia that can progress to cervical cancer. The term carcinoma ''in situ'' may be used interchangeably with high-grade SIL.<ref>{{cite web|title=Understanding Cervical Changes |url=http://www.cancer.gov/cancertopics/understanding-cervical-changes/understandingcervicalchanges.pdf |website=National Cancer Institute |publisher=National Institute of Health |access-date=17 June 2014 }}{{dead link|date=November 2016 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> * Ductal carcinoma ''in situ'' of the breast is the most common precancer in women. * Bowen's disease is a squamous carcinoma ''in situ'' of the skin. * Colon polyps often contain areas of CIS that will almost always transform into colon cancer if left untreated. * High-grade prostatic intraepithelial neoplasia is equivalent to CIS of the prostate. * Bronchioloalveolar carcinoma (BAC) of the lung is the only form of CIS that can kill directly because, in rare cases (the "pneumonic form"), it expands greatly and fills the lungs, preventing breathing and causing other dire effects on the host. Thus, the pneumonic form of BAC is a true malignant entity, but is not "invasive" in the classical sense. For this reason, it is considered a form of CIS by pathologists, but not by oncologists or surgeons, and inclusion of this form of cancer among the types of CIS is controversial.
==Treatment==
Carcinoma ''in situ'' is, by definition, a localized phenomenon, with no potential for metastasis unless it progresses into cancer. Therefore, its removal eliminates the risk of subsequent progression into a life-threatening condition.
Some forms of CIS (e.g., colon polyps and polypoid tumours of the bladder) can be removed using an endoscope, without conventional surgical resection. Dysplasia of the uterine cervix is removed by excision (cutting it out) or by burning with a laser. Bowen's disease of the skin is removed by excision. Other forms require major surgery, the best known being intraductal carcinoma of the breast (also treated with radiotherapy).
== References == {{reflist}}
== External links == {{Medical resources | DiseasesDB = | ICD10 = | ICD9 = | ICDO = {{ICDO|8010|2}} | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = | SNOMED CT = 68956006 }} {{Tumors}}
Category:Histopathology Category:Carcinoma