Myoepithelial cells

MyPathologyReport
November 30, 2023

Myoepithelial cells are specialized muscle-like cells found in various tissues and organs of the body, particularly in structures that contain glandular or secretory elements. Myoepithelial cells are unique in that they combine the features of two different types of cells: muscle cells called myocytes and epithelial cells. This combination of features gives myoepithelial cells the ability to contract and exert mechanical force, similar to muscle cells and to connect like epithelial cells. They are responsible for aiding in the movement of secretions from the glandular cells into the ducts that lead to the body’s various openings or cavities.

Where are myoepithelial cells normally found in the body?

Myoepithelial cells are found in tissues and organs throughout the body.

Some common locations where myoepithelial cells are found include:

• Salivary glands: Myoepithelial cells are present in the salivary glands and help in the release of saliva into the oral cavity.
• Mammary glands: In the breast tissue, myoepithelial cells surround the alveoli and ducts, aiding in the expulsion of milk during breastfeeding.
• Mammary ducts: They are also found in the mammary ducts, where they help move milk towards the nipple.
• Sweat glands: Myoepithelial cells are located in sweat glands and assist in pushing sweat to the skin’s surface, helping regulate body temperature.
• Lacrimal glands: Myoepithelial cells are present in the tear-producing glands of the eyes, contributing to tear secretion.
• Prostate gland: In the male reproductive system, myoepithelial cells are found in the prostate gland, aiding in the release of prostatic fluid.
• Bronchioles: Myoepithelial cells are located in the walls of bronchioles in the respiratory system, helping to expel mucus and other secretions from the airways.
• Exocrine pancreas: Myoepithelial cells are present in the pancreatic ducts and assist in moving digestive enzymes into the small intestine.

What types of cancers are made up of myoepithelial cells?

Myoepithelial carcinoma is a type of cancer made up entirely of myoepithelial cells. This type of cancer is typically found in the salivary glands but rarely it can be found in the breast, lungs, or soft tissue. A variety of other cancers including epithelial-myoepithelial carcinoma and adenoid cystic carcinoma are made up of myoepithelial cells and other cell types.

What is a benign tumour made up of myoepithelial cells?

A myoepithelioma is a benign (noncancerous) type of tumour made up entirely of myoepithelial cells. This type of tumour is most common in the salivary glands although it can also be found in the skin, lungs, and soft tissue. Some other rare benign tumours including adenomyoepithelioma of the breast are made up of myoepithelial cells and other cell types.

What are myoepithelial cell markers?

Markers of myoepithelial cells include smooth muscle antigen (SMA), muscle-specific antigen (MSA), calponin, cytokeratin 5 (CK5), p40, and p63.

What does it mean if myoepithelial cells are absent in a tumour?

For some types of tumours, pathologists look for myoepithelial cells to distinguish between a benign (noncancerous) tumour and a malignant (cancerous) tumour. This is because myoepithelial cells are typically absent or lost in malignant tumours but are still present in benign tumours or precancerous conditions. For example, pathologists use the presence or absence of these cells to distinguish between ductal carcinoma in situ (DCIS) and invasive ductal carcinoma in the breast.

About this article

This article was written by doctors to help you read and understand your pathology report. Contact us if you have questions about this article or your pathology report. For a complete introduction to your pathology report, read this article.

Other helpful resources

Pathology Atlas