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Myoepithelial carcinoma (MC)

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Myoepithelial carcinoma

Myoepithelial carcinoma (MC) is a rare and potentially aggressive type of salivary gland cancer. It makes up less than 2% of all salivary gland tumours [1]. MC arises from myoepithelial cells, which can contract and help the salivary gland expel saliva.

Diagnosis

Myoepithelial carcinoma can be difficult to diagnose because it can look very different under the microscope from case to case. It often behaves in a more aggressive way than some other salivary gland cancers [2, 3].

Some cases of MC develop on their own (de novo), while others arise from a pre-existing benign tumour (such as a myoepithelioma or a pleomorphic adenoma) that has turned malignant over time [1, 4].

Myoepithelial carcinoma most commonly arises in the parotid gland, but it can also occur in the submandibular gland or in the minor salivary glands of the mouth and throat [2, 4]. It can occur at any age, but it is most frequently diagnosed in middle-aged adults, it is equally common is males and females [3, 5].

Symptoms depend on the size and location of the tumour, but may include:

  • A slow- or fast-growing lump in the cheek, jaw, or mouth
  • Pain or tenderness
  • Facial weakness or numbness if the facial nerve is affected
  • Swelling or ulceration if the tumour is large or near the surface [2, 4]

Because MC can be more aggressive than other salivary gland tumours, symptoms may develop more rapidly and the tumour may invade nearby tissues or spread to lymph nodes.

Under the microscope, myoepithelial carcinoma is made up of myoepithelial cells which come in a variety of different shapes. This variation can make diagnosis difficult. Special techniques and are often used to confirm the diagnosis [3, 6].

Treatment

Treatment for myoepithelial carcinoma usually involves a combination of surgery and radiotherapy. The choice of treatment depends on the tumour’s size, location, and how far it has spread. Chemotherapy is less commonly used but may be considered in advanced cases or if the tumour has spread to other locations, although its effectiveness is not well established [2, 3, 7]

Because of its potential to spread and recur, treatment should ideally be managed in a specialist centre with experience in rare salivary gland cancers.

The outlook for people with myoepithelial carcinoma depends on several factors, including:

  • Whether the tumour is low-grade or high-grade (more aggressive)
  • Whether it has spread to lymph nodes or other parts of the body
  • Whether it was fully removed by surgery

Reported five-year range from 50% to 80%, but long-term follow-up is essential, as some tumours can recur or spread years after initial treatment [2, 4, 7].

References

  1. Alsanie I, Shah KA, Adkins DR, et al. Distribution and Frequency of Salivary Gland Tumours: An International Multicenter Study. Head Neck Pathol. 2022;16(4):1043–1054.
  2. Gnepp DR, Bishop JA, eds. Diagnostic Surgical Pathology of the Head and Neck. 3rd ed. Philadelphia: Elsevier; 2021.
  3. Seethala RR, Hunt JL. Epithelial–myoepithelial carcinoma and myoepithelial carcinoma of the salivary glands. Arch Pathol Lab Med. 2009;133(2):287–293.
  4. Savera AT, Sloman A, Huvos AG, Klimstra DS. Myoepithelial carcinoma of the salivary glands: a clinicopathologic study of 25 patients. Am J Surg Pathol. 2000;24(6):761–774.
  5. Kane SV, Bagwan IN. Myoepithelial carcinoma of salivary glands: a clinicopathologic study of 51 cases. Ann Diagn Pathol. 2015;19(1):10–14.
  6. Antonescu CR, Zhang L, Shao SY, et al. EWSR1-POU5F1 fusion in myoepithelial tumors. Genes Chromosomes Cancer. 2010;49(6):569–580.
  7. National Comprehensive Cancer Network (NCCN). NCCN Clinical Practice Guidelines in Oncology: Head and Neck Cancers, Version 2.2024. Plymouth Meeting, PA: NCCN; 2024.

Useful resources

Read more about how to get your tumour profiled and add to the research biobank at the Christie Hospital in Manchester, UK here:

Last updated May 2025