Salivary gland cancer is a malignant tumour that starts in cells of a salivary gland. Malignant means that it can spread, or metastasize, to other parts of the body.
The salivary glands make a fluid called saliva. Saliva helps you digest food. It also protects your mouth and throat from infection. There are 3 pairs of major salivary glands. The parotid glands are in front of each ear on either side of your face. The submandibular glands are behind the lower jaw, just under the tongue. The sublingual glands are under the tongue, deep in the floor of the mouth. There are also hundreds of small minor salivary glands in your upper airway and digestive tract.
Cells in a salivary gland sometimes change and no longer grow or behave normally. These changes may lead to non-cancerous, or benign, tumours such as pleomorphic adenoma (also called benign mixed tumour) or papillary cystadenoma lymphomatosum (also called Warthin’s tumour).
In some cases, changes to salivary gland cells can cause cancer. Mucoepidermoid carcinoma (MEC) is the most common type of salivary gland cancer. It usually develops in the parotid gland. Adenoid cystic carcinoma is the second most common type of salivary gland cancer. It usually develops in a minor salivary gland. Other types of cancer can also develop in the salivary glands, including acinic cell carcinoma, salivary duct carcinoma and primary salivary gland lymphoma.
Very rare types of salivary gland cancer can also develop. These include mixed malignant tumours, carcinoma ex-pleomorphic adenocarcinoma and carcinosarcoma.
Salivary gland tumours occur most often in the parotid gland, but these tumours are usually benign. Tumours that develop in the submandibular glands and minor salivary glands are more likely to be malignant.
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