{{Short description|Localized necrosis of adipose tissue}} {{cs1 config|name-list-style=vanc|display-authors=6}} {{Infobox medical condition (new) | name = Fat necrosis | synonyms = also known as Balser's necrosis | image = Breast tissue showing fat necrosis 4X.jpg | caption = Micrograph of breast tissue showing fat necrosis. H&E stain | pronounce = | field = Pathology | symptoms = | complications = | onset = | duration = | types = | causes = | risks = | diagnosis = | differential = | prevention = | treatment = | medication = | prognosis = | frequency = | deaths = }}
'''Fat necrosis''' is necrosis affecting fat tissue (adipose tissue).<ref name="cite709b1306">{{Cite book | veditors = Strayer DS, Rubin E, Saffitz JE, Schiller AL | title = Rubin's Pathology: Clinicopathologic Foundations of Medicine | location = Philadelphia | pages = 34–35 | year = 2015 | publisher = Wolters Kluwer Health | isbn = 978-1-4511-8390-0 | edition = 7th }}</ref> The term is well-established in medical terminology despite not denoting a specific pattern of necrosis.<ref name="citee87cd98b">{{Cite book | veditors = Kumar V, Abbas AK, Aster JC | title = Robbins and Cotran pathologic basis of disease | location = Philadelphia, PA | pages = 43–44 | date = 2015 | publisher = Elsevier/Saunders | isbn = 978-1-4557-2613-4 | edition = Ninth }}</ref> Fat necrosis may result from various injuries to adipose tissue, including: physical trauma, enzymatic digestion of adipocytes by lipases,<ref name="Cross_2013">{{Cite book | vauthors = Cross SS | title = Underwood's Pathology | page = 85 | year = 2013 | isbn = 978-0-7020-4672-8 | edition = 6th | publisher = Churchill Livingstone }}</ref> radiation therapy,<ref>{{Cite web | title = fat necrosis | date = 2011-02-02 | url = https://www.cancer.gov/publications/dictionaries/cancer-terms/def/fat-necrosis | website = www.cancer.gov | language = en }}</ref> hypoxia, or inflammation of subcutaneous fat (panniculitis).
The gross appearance of fat necrosis is as an irregular, chalky white area within otherwise normal adipose tissue.<ref name="cite709b1306" /> Rarely, mobile encapsulated fat necrosis may instead appear as a mobile, firm, fibrous nodule deep to the skin.<ref>{{Cite journal |last1=Sheehan |first1=Connor |last2=Tran |first2=Theresa |last3=Mollaee |first3=Mehri |last4=Hsu |first4=Sylvia |date=2025-01-27 |title=A Case of Three Upper Extremity Lesions of Mobile Encapsulated Fat Necrosis in One Patient |journal=Cureus |volume=17 |issue=1 |article-number=e78080 |language=en |doi=10.7759/cureus.78080 |doi-access=free |issn=2168-8184 |pmc=11865868 |pmid=40018461}}</ref>
== Pathophysiology ==
=== Trauma === Traumatic injury of adipose tissue liberates stored fat<ref name="cite709b1306" /><ref name="Cross_2013" /> as well as lipases<ref name="cite709b1306" /> from adipocytes. The extracellular fat then elicits a swift inflammatory response, attracting macrophages and polymorphonuclear leukocytes which proceed to phagocytose the freed fat. The process eventually leads to fibrosis. The necrotic tissue may eventually form a palpable mass (especially if situated at a superficial site like the breast).<ref name="Cross_2013" />
Traumatic fat necrosis commonly affects the breast and may resemble a tumour (especially in case of calcification of the necrotic mass).<ref name="cite709b1306" />
=== Enzymatic digestion === Pancreatic conditions like acute pancreatitis,<ref name="Cross_2013" /> pancreatic carcinoma, and pancreatic trauma<ref name="Lee_1979">{{cite journal | vauthors = Lee PC, Howard JM | title = Fat necrosis | journal = Surgery, Gynecology & Obstetrics | volume = 148 | issue = 5 | pages = 785–789 | date = May 1979 | pmid = 432796 }}</ref> result in liberation of pancreatic lipase which proceeds to digest fat to form free fatty acids which subsequently combine with calcium to form soapy precipitates.<ref name="Cross_2013" /><ref name="citee87cd98b" />
Although the peripancreatic region is the most commonly affected (due to direct contact with enzymes), associated fat necrosis may occur throughout the body in subcutaneous tissue, hand and foot joints, and bone marrow. These extrapancreatic complications are known as pancreatic panniculitis.<ref name="Lee_1979" />
== Clinical significance ==
=== Breast fat necrosis ===
==== Causes ==== Examples of causes include but are not limited to:{{Citation needed|date=June 2024}}
* Breast trauma (e.g. seat belt injury from a car accident) * Breast surgery **Fine needle aspiration biopsy and cytology (FNAB, FNAC) **Radiotherapy ** Lumpectomy ** Reduction mammoplasty **Breast reconstruction * Pancreatic disease ** Acute pancreatitis ** Pancreatic cancer ** Pancreatic injury * Some forms of panniculitis ** Subcutaneous fat necrosis of the newborn ** Weber–Christian disease * Polyarteritis nodosa<ref name="Kerridge_2015">{{cite journal | vauthors = Kerridge WD, Kryvenko ON, Thompson A, Shah BA | title = Fat Necrosis of the Breast: A Pictorial Review of the Mammographic, Ultrasound, CT, and MRI Findings with Histopathologic Correlation | journal = Radiology Research and Practice | volume = 2015 | article-number = 613139 | date = 2015-03-16 | pmid = 25861475 | pmc = 4378709 | doi = 10.1155/2015/613139 | doi-access = free }}</ref><ref name="Genova_2020">{{Citation |last1=Genova |first1=Rafaella |title=Breast Fat Necrosis |date=2020 |work=StatPearls |url=https://www.ncbi.nlm.nih.gov/books/NBK542191/ |access-date=2020-11-12 |place=Treasure Island (FL) |publisher=StatPearls Publishing |pmid=31194348 |last2=Garza |first2=Robert F.}}</ref>
==== Epidemiology ==== Fat necrosis in the breast occurs around 0.6%, this represents 2.75% of lesions that end up being benign. However, 0.8% of fat necrosis occurs from tumors of the breast, 1–9% occurs in breast reduction surgery. Individuals that are high risk include women around the age of 50yrs along with pendulous breasts.<ref name="Rice_2013">{{Cite journal | vauthors = Rice H, Warland J | title = Bearing Witness: Midwives experiences of witnessing traumatic birth | journal = Women and Birth | volume = 26 | pages = S39 | date = October 2013 | doi = 10.1016/j.wombi.2013.08.215 | issn = 1871-5192 }}</ref>
== See also == *Caseous necrosis *Coagulative necrosis *Liquefactive necrosis *Myospherulosis *Necrosis
== References == {{Reflist}}
{{Pathology}}
== External links == {{Medical resources | DiseasesDB = | ICD10 = | ICD9 = | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = | eMedicineTopic = | MeshID = D005218 }} * [http://breast-cancer.ca/necrofat/ Fat Necrosis of the breast]
{{DEFAULTSORT:Fat Necrosis}} Category:Pathology Category:Necrosis Category:Breast diseases Category:Pancreas disorders