The salivary glands are located around the mouth. The saliva produced by the salivary glands moistens food and helps with chewing and swallowing; it also contains an enzyme called Salivary Amylase that begins the process of digestion.
There are three main pairs of salivary glands. The largest is the parotid gland, located in each cheek over the jaw in front of the ears. Two submandibular glands are at the back of the mouth on both sides of the jaw. Two sublingual glands are under the floor of the mouth. There are also thousands of minor salivary glands that are widely distributed in the mucosa of the lips, cheeks, hard and soft palate, uvula, the floor of the mouth, tongue, and peritonsillar region. All of the salivary glands empty saliva into the mouth through ducts that open at various locations in the mouth.
About 85% of salivary gland tumours occur in the parotid glands, and 75 to 80% are benign and slow-growing.
Benign Tumours
- The most common type is a pleomorphic adenoma (mixed tumour). They are slow-growing and lobular and may become very large without interfering with facial nerve function. Malignant transformation is possible, but this usually occurs only after the benign tumour has been present for more than a decade.
- Other benign tumours include monomorphic adenoma, oncocytoma, and papillary cystadenoma lymphomatosum (Warthin’s tumour). These tumours rarely recur or become malignant.
Malignant Salivary Gland Tumours
- Malignant tumours are less common and are characterised by rapid growth or a sudden growth spurt. They are firm, nodular, and can be fixed to adjacent tissue. Pain and neural involvement (facial nerve paralysis) are common. Eventually, the overlying skin or mucosa may become ulcerated, or the adjacent tissues may become invaded. Surgery, followed by radiation therapy, is the treatment of choice for resectable disease.
- Some malignant tumours are:
- Mucoepidermoid carcinoma is the most common salivary gland cancer, typically occurring in the age group of 20 to 50 years. It can manifest in any salivary gland, often in a minor salivary gland of the palate.
- Adenoid cystic carcinoma is the most common malignant tumour of minor salivary glands. Its peak incidence is between the age group of 40 to 60 years. Its symptoms include severe pain and, often, facial nerve paralysis.
- Acinic cell carcinoma, a common parotid tumour, occurs in people in the age group of 40 to 50 years. This carcinoma is slow-growing.
- Carcinoma ex pleomorphic adenoma is an adenocarcinoma arising from a preexisting benign tumour.
