Exocrine secretion
Merocrine or eccrine – by exocytosis
Apocrine – by membrane budding (loss of cytoplasm)
Holocrine – by membrane rupture

Apocrine (/ˈæpəkrɪn/)[1] glands are a type of exocrine gland, which are themselves a type of gland, i.e. a group of cells specialized for the release of secretions. Exocrine glands secrete by one of three means: holocrine, merocrine and apocrine. In apocrine secretion, secretory cells accumulate material at their apical ends, and this material then buds off from the cells, forming extracellular vesicles. The secretory cells therefore lose part of their cytoplasm in the process of secretion.

Apocrine secretion
Apocrine gland

An example of true apocrine glands is the mammary glands, responsible for secreting breast milk.[2] Apocrine glands are also found in the anogenital region and axillae.[3]

Apocrine secretion is less damaging to the gland than holocrine secretion (which destroys a cell) but more damaging than merocrine secretion (exocytosis).

Apocrine metaplasiaEdit

 
Micrograph showing apocrine metaplasia of the breast. H&E stain.

Apocrine metaplasia is a reversible transformation of cells to an apocrine phenotype. It is common in the breast in the context of 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.[4] This type of metaplasia represents an exception to the common rule of metaplasia increasing the risk for developing cancer; apocrine metaplasia doesn't increase at all the possibility of getting breast cancer.[citation needed]

Apocrine carcinomaEdit

Apocrine carcinoma is a very rare form of female breast cancer. The rate of incidence varies from 0.5 to 4%.[5] Cytologically, the cells of apocrine carcinoma are relatively large, granular, and it has a prominent eosinophilic cytoplasm.[6] When apocrine carcinoma is tested as a “triple negative", it means that the cells of the patient cannot express the estrogen receptor, progesterone receptor, or HER2 receptor.[7]

ReferencesEdit

  1. ^ "Apocrine | Meaning of Apocrine by Lexico". Lexico Dictionaries | English.
  2. ^ Mescher AL, "Chapter 4. Epithelial Tissue" (Chapter). Mescher AL: Junqueira's Basic Histology: Text & Atlas, 12e: http://www.accessmedicine.com/content.aspx?aID=6180489.
  3. ^ Murphrey, Morgan B.; Safadi, Anthony O.; Vaidya, Tanvi (August 10, 2020). Histology, Apocrine Gland. StatPearls Publishing. PMID 29489220.
  4. ^ Dr Ayush Goel and Radswiki et al. Apocrine metaplasia of the breast.http://radiopaedia.org/articles/apocrine-metaplasia-of-the-breast
  5. ^ 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.
  6. ^ "Archived copy". Archived from the original on 2000-03-12. Retrieved 2014-11-03.{{cite web}}: CS1 maint: archived copy as title (link) (accessed November 3, 2014)
  7. ^ Potter, Michelle. "A[pcrome Breast Cancer - Johns Hopkins Kimmel Cancer Center". www.hopkinsmedicine.org.

External linksEdit