Editing Apocrine

{{Short description|Classification of secretion of exocrine glands}}
{{Exocrine secretion}}
'''Apocrine''' ({{IPAc-en|ˈ|æ|p|ə|k|r|ɪ|n}})<ref>{{Cite web|url=https://www.lexico.com/definition/apocrine|archive-url=https://web.archive.org/web/20200726070752/https://www.lexico.com/definition/apocrine|url-status=dead|archive-date=July 26, 2020|title=Apocrine &#124; Meaning of Apocrine by Lexico|website=Lexico Dictionaries &#124; English}}</ref>  is a term used to classify the mode of [[secretion]] of [[exocrine glands]]. In apocrine secretion, secretory cells accumulate material at their [[apical (anatomy)|apical]] ends, often forming [[Bleb (cell biology)|blebs]] or "snouts", and this material then [[Budding|buds off]] from the cells, forming extracellular [[vesicle (biology and chemistry)|vesicle]]s. The secretory cells therefore lose part of their [[cytoplasm]] in the process of secretion.

An example of true apocrine glands is the [[mammary gland]]s, responsible for secreting breast milk.<ref>Mescher AL, "Chapter 4. Epithelial Tissue" (Chapter). Mescher AL: Junqueira's Basic Histology: Text & Atlas, 12e: http://www.accessmedicine.com/content.aspx?aID=6180489.</ref> Apocrine glands are also found in the anogenital region and [[axilla]]e.<ref>{{Cite book|last1=Murphrey|first1=Morgan B.|url=https://www.ncbi.nlm.nih.gov/books/NBK482199/|title=Histology, Apocrine Gland|last2=Safadi|first2=Anthony O.|last3=Vaidya|first3=Tanvi|date=August 10, 2020|publisher=StatPearls Publishing|pmid=29489220}}</ref>

Apocrine secretion is less damaging to the gland than holocrine secretion (which destroys a cell) but more damaging than merocrine secretion ([[exocytosis]]).
<gallery mode=packed heights=160>
File:405 Modes of Secretion by Glands Apocrine.png|Apocrine secretion
Image:Apocrine.jpg|Apocrine gland
File:Histology of apocrine cells.png|Histology of apocrine cells, H&E stain.
</gallery>

==Apocrine metaplasia==
[[File:Histopathology of apocrine metaplasia of breast, annotated.png|thumb|290px|[[Micrograph]] showing apocrine [[metaplasia]] of the breast with typical features,<ref>Image by Mikael Häggström, MD. Reference for findings: {{cite web|url=https://www.pathologyoutlines.com/topic/breastapocrinemetaplasia.html|title=Apocrine metaplasia|author=Carlos C. Diez Freire, M.D., Shahla Masood, M.D.|website=Pathology Outlines}} Last author update: 28 May 2020.</ref> including apical snouts with eosinophilic granules. [[H&E stain]].]]
'''Apocrine metaplasia''' is a reversible transformation ([[metaplasia]]) of cells to an apocrine [[phenotype]]. It is common in the breast in the context of [[fibrocystic breast changes|fibrocystic change]]. It is seen in women mostly over the age of 50 years. Metaplasia happens when there is an irritation to the breast (breast cyst). Apocrine-like cells form in a lining of developing microcysts, due to the pressure buildup within the lumen. The pressure build up is caused by secretions.<ref>Dr Ayush Goel and Radswiki et al. Apocrine metaplasia of the breast.http://radiopaedia.org/articles/apocrine-metaplasia-of-the-breast</ref> This type of metaplasia represents an exception to the common rule of metaplasia increasing the risk for developing cancer in that apocrine metaplasia doesn't increase the possibility of developing breast cancer.<ref>{{Cite journal |last1=Wells |first1=C A |last2=El-Ayat |first2=G A |date=December 2007 |title=Non-operative breast pathology: apocrine lesions |journal=Journal of Clinical Pathology |volume=60 |issue=12 |pages=1313–1320 |doi=10.1136/jcp.2006.040626 |issn=0021-9746 |pmc=2095572 |pmid=18042688}}</ref> Metaplastic apocrine cells belong to the category of [[oncocytes]], which are a group characterized by abundant [[acidophilic]], granular cytoplasm (from the Greek root onco-, which means mass, bulk).

==Apocrine ductal carcinoma ''in situ''==
{{Main|Pure apocrine carcinoma of the breast#Apocrine ductal carcinoma in situ}}
'''Apocrine ductal carcinoma ''in situ'' ''' (ACDIS) is a very rare breast carcinoma which is regarded as a variant of the [[ductal carcinoma in situ]] breast tumors. ACDIS tumors have microscopic [[histopathology]] features that are similar to [[pure apocrine carcinoma of the breast]] tumors but differ from them in that they are completely localized, i.e. have not invaded nearby tissues or metastasized to distant tissues.<ref name="pmid34537861">{{cite journal | vauthors = Quinn CM, D'Arcy C, Wells C | title = Apocrine lesions of the breast | journal = Virchows Archiv | volume = 480 | issue = 1 | pages = 177–189 | date = January 2022 | pmid = 34537861 | pmc = 8983539 | doi = 10.1007/s00428-021-03185-4 | url = }}</ref>

==Apocrine carcinoma==
{{Main|Pure apocrine carcinoma of the breast}}
''Apocrine [[carcinoma]]'' is a very rare form of female breast cancer. The rate of incidence varies from 0.5 to 4%.<ref>Khandeparkar, Siddhi Gaurish Sinai, Sanjay D. Deshmukh, and Pallavi D. Bhayekar. "A rare case of apocrine carcinoma of the breast: Cytopathological and immunohistopathological study." Journal of Cytology/Indian Academy of Cytologists 31.2 (2014): 96.</ref> Cytologically, the cells of apocrine carcinoma are relatively large, granular, and it has a prominent [[eosinophilic]] cytoplasm.<ref>{{cite web|url=http://path.upmc.edu/cases/case209/dx.html |title=Final Diagnosis -- Case 209 |access-date=2014-11-03 |url-status=dead |archive-url=https://web.archive.org/web/20000312050409/http://path.upmc.edu/cases/case209/dx.html |archive-date=2000-03-12 }} (accessed November 3, 2014)</ref> When apocrine carcinoma is tested as a [[Triple-negative breast cancer|“triple negative"]], it means that the cells of the patient cannot express the [[estrogen receptor]], [[progesterone receptor]], or [[HER2]] receptor.<ref>{{Cite web|url=https://www.hopkinsmedicine.org/kimmel_cancer_center/centers/breast_cancer_program/treatment_and_services/rare_breast_tumors/apocrine_breast_cancer|title=A[pcrome Breast Cancer - Johns Hopkins Kimmel Cancer Center|first=Michelle|last=Potter|website=www.hopkinsmedicine.org}}</ref>

==References==
{{Reflist}}

==External links==
* [http://www.lab.anhb.uwa.edu.au/mb140/CorePages/Epithelia/Epithel.htm#Secretory Diagram at uwa.edu.au]

{{Glands}}

[[Category:Apocrine| ]]
[[Category:Exocrine system]]