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Salivary Gland

Salivary glands include major and minor glands. Major salivary glands include parotid glands that are located in front and below the ears, the submandibular glands that are under the lower jaw on each side of the neck, and the sublingual glands that are under the tongue and the floor of mouth area. These are in pair, one in each side.


Minor salivary gland are located under the mucosal lining of all part of mouth, lip, throat, nose, sinuses, voice box.


What Is The Function Of The Salivary Glands?

Salivary glands produce saliva. Saliva plays a role in initiating the digestion of food. Saliva also provides continuing moisture for the mouth, hence preventing dryness, constantly washing the mouth as one produces a constant flow of saliva that is being swallowed. Saliva helps keeping the tongue and the teeth healthy. There is accelerated dental decay when one has very dry mouth. This is well observed in individuals who undergo radiotherapy for treatment of mouth or throat cancer, where radiotherapy results in loss of salivary function and permanent dryness of mouth. Such individuals need to keep very intense dental care with frequent visit to dentist to keep their teeth healthy. Of course loss of one salivary gland alone would not give any significant loss or reduction in saliva production. Often when radiotherapy is used for various tumors in head and neck region every attempt is made to spare major salivary glands when technically and oncologically feasible and possible.


What Are The Common Problems That can Occur with The Salivary Gland?

Major salivary glands can become infected occasionally. Infection in these glands often results from dehydration which leads to sluggish saliva flow and bacteria getting in from the mouth and causing infection. Infection can also occur if there is obstruction to the saliva flow out of the saliva gland.


The most common cause of obstruction is tiny stones that can develop within the collecting ducts of the saliva glands. Such stones gradually develop from microscopic deposits of calcium or other minerals within the saliva. The build up results in gradual enlargement of the stone and obstruction of gland by the stone. Read further on saliva gland stones here.


What are the tumors of salivary gland?

Parotid Gland

Of all parotid gland tumors about 80% are benign. The most common benign tumor of the parotid gland is pleomorphic adenoma (also called benign mixed tumor) It constitutes approximately 80% of benign salivary gland tumors. The next most common benign tumor is called Warthin's tumor. This tends to occur more commonly in older individuals.


Cancerous tumors constitute about 20% of parotid tumors. There are several varieties of such tumors. However, the most common are called mucoepidermoid cancer and adenoid cystic cancer. There are several other kinds that are more rare.


Same kind of tumors occur in other salivary glands, but with different distribution. Of note, there are large number of minor salivary glands throughout the lining of mouth, palate, throat, and even the nose and sinuses. Therefore salivary gland tumors can occur in any of these areas. They may even occur in voice box, upper airway of lung (ie trachea and bronchi).


How do salivary gland tumors present?

Most of these tumors present as an asymptomatic mass. For parotid gland which is located right in front and below the ear a mass which most often is painless and non-tender may be either noted on touching and feeling the area. Often the mass has been there for long time and very slowly growing. This slow and almost un-noticeable growth is deceiving. The lack of pain or discomfort, and slow growth are NOT sign of benign tumor. Cancerous tumors are more often than not totally painless and often slow growing.


How are salivary gland tumors diagnosed and investigated ?

When as mass is noted in neck which may or may not be from salivary glands, a consultation to ENT-Head and Neck surgeon is warranted. Based on examination in the office the physician will have a pretty good idea if indeed the mass arises from one of the major salivary glands, by noting the exact location of the mass.


Two tests are most important in determining the nature of the mass. Fine needle aspiration biopsy and a radiologic imaging which is often a CT scan. Other imaging or testing may be ordered by the physician selectively. CT or any other scan does not give the diagnosis. It helps the surgeon to confirm the exact location of the mass, it's size, whether it is solid or cystic or combination of the two, whether it is single or multiple, its borders etc. These are useful information for diagnosis and deciding in further course of management. Sometimes masses are located outside of the the major salivary glands, but adjacent to them. Not all masses or bumps of the major salivary gland are tumors. Benign cysts or obstructive cysts also present as a mass.


Fine Needle Biopsy: This test is the most important. It is done in the office by the head and neck surgeon who is experienced in routinely performing it. A fine needle, coupled to a syringe, is inserted into the mass directly through the skin (not unlike a blood test). Typically 3 to 4 passes are done which each insertion. The goal is to capture enough of the tumor cells in the needle which is then smeared on a glass slide as well as washing the rest of the content of the needle in a special fixative solution. The slide and the solution is then sent to the cytopathology lab for analysis.


This is a very safe and effective method of either getting a exact diagnosis or at least narrowing down the possible diagnosis. The needle biopsy takes less than 5-10 seconds to perform, so it is very well tolerated by the patient. Some times it may need to be repeated if the physician judges that perhaps not enough cells are captured by the first pass.


Fine needle biopsy does not cause spread of the tumor. It is the established, standard and safe practice and highly useful in planning care. It may help to avoid unnecessary major operations when a completely benign and non-neoplastic (non-tumor) condition is diagnosed. It can also help avoid major surgery in case of cancers such as lymphoma which is typically treated by non surgical methods (chemotherapy and or radiotherapy). A smaller surgery for biopsy purpose would be adequate, essentially for establishing the diagnosis and sub-typing of lymphoma. Needle biopsy when showing a specific type of salivary gland tumor or any other tumor can help to council the patient much better in preparation for care.


How are salivary gland tumors treated?

Salivary gland tumors are treated by surgical removal of them. In case of benign tumors surgery with complete removal of tumor is the definitive and curative treatment and no other treatment (ie radiotherapy or chemotherapy) is needed.


In case salivary gland cancers again surgery is the main and most effective treatment. However, sometimes this is followed by radiotherapy.


Will chemotherapy be required for the treatment of salivary gland cancer?

No, generally salivary gland tumors are not considered to be chemosensitive to the current chemotherapy drugs available.


Will radiotherapy be required for the treatment of salivary gland cancer?

This is individualized. Need for radiotherapy following the surgical removal of the salivary gland cancers is highly individualized based on number of factors that your head and neck surgeon considers. These factors include the exact kind of cancer with its grade (high grade vs low grade), the size of tumor, the exact location of the tumor, the status of margins of excision, and completeness of resection etc. However, complete removal of tumor with negative margins is the most important aspect of treatment.