Salivary Gland Cancer
About the Saliva Glands
A saliva gland is a collection of cells that produce and allow the drainage for saliva. Saliva is important for lubricating the mouth (allowing speech and swallowing), digestion, immune function and for protection against dental caries. The glands are composed of a number of different cell types including salivary gland cells (mucous or acinar), muscle cells, lymphoid cells and lymph nodes. Due to this variety of cells, there are a number of tumours that can originate from these different cells.
The saliva glands are described as major or minor glands. The major glands are named glands and include the parotid gland (in front of the ear), submandibular gland (under the jaw) and sublingual gland (under the tongue). These glands drain into the mouth via different ducts (or pipes). There are hundreds of minor salivary glands found throughout the mouth.
What are the symptoms of a salivary gland tumour?
Salivary gland tumours typically present as a lump. This could be identified by the individual or noticed by someone else. Occasionally, these lumps can be identified incidentally on imaging (typically CT or MRI). Alternatively these tumours can cause sensory disturbances such as pins and needles or numbness, most commonly to the lip or tongue.
Benign tumours tend to cause no other symptoms other than swelling.
Malignant tumours may also present as a painless lump. For advanced lesions, it may cause ulceration of the overlying skin or weakness of the face due to involvement of the facial nerve.
Salivary gland tumours
Saliva glands can have malignant (cancer) and benign (non-cancerous) tumours. In the major glands, the most common lesions are benign. The tumours of the minor salivary glands are most commonly malignant.
To read more about the different kinds of tumours, please see below.
Types of Salivary gland (malignant) tumours
Metastatic squamous cell carcinoma
This is the most common cancer found in the major salivary glands. It is as the result of a skin cancer that has the ability to spread via the lymphatic system. The parotid and submandibular glands contain lymph nodes (glands) as found in the neck and as a result act as a common pathway for skin cancers to spread.
Mucoepidermoid carcinoma
This is the most common malignant tumour that originates in the salivary gland. These cancers can be considered low grade (less aggressive) or high grade (aggressive). This requires the tumour to be removed and reviewed by a pathologist (specialist doctor).
Carcinoma ex-pleomorphic adenoma
This is a tumour initially begins as a pleomorphic adenoma (LINK), a benign tumour. If left, it has a risk of transforming into this type of cancer. The quoted risk is approximately 10% transformation rate in 10 years.
Secretory carcinoma
This is a less aggressive tumour originating in the salivary glands.
Adenoid cystic carcinoma
An adenoid cystic carcinoma is considered a relentless cancer. This type of cancer can spread (metastasize) early and along adjacent nerves. Overall, it has a poorer prognosis compared with other salivary gland tumours and the ability to return years after its initial treatment.
Salivary duct carcinoma
A salivary duct carcinoma is an aggressive cancer. It spreads early to the lymph nodes (glands) of the neck.
Salivary Gland (benign) Tumours
Pleomorphic adenoma
The pleomorphic adenoma is the most common benign salivary gland tumour. It is the cause for nearly 2/3rds of parotid gland lumps. It has a thin capsule which makes it prone to rupture when being removed. It also has frond like extensions through the capsule which is thought to be associated with the pleomorphic adenoma coming back (recurring). If there is rupture during your procedure, there are some techniques to help reduce the risk of the tumour recurring. While surgery is the most common treatment, radiation therapy has been used to reduce the risk of recurrence.
Papillary cystadenoma lymphomatosum (Warthin’s) tumour
A Warthin’s tumour is the second most common benign salivary gland tumour. It is most common in males who have smoked. It may be found bilaterally in up to 1:10 people. The lesion if removed completely does not recur.