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Salivary glands are organs or structures located in our head and neck region that produce a digestive aid secretion (saliva) and drain it into connected channels in the mouth, throat, pharynx, nose, sinuses, and other areas.
We have six major salivary glands, three on each side of our face, as well as hundreds of minor (microscopic) salivary glands scattered throughout the mucous membrane. The secretion they produce not only aids in digestion but also provides the necessary moisture for the mouth, throat, nose, and laryngeal cavities.
Below, you can find general information about salivary gland tumors and cancers, as well as detailed information about surgery and the postoperative process.
Please feel free to contact me for more information on salivary gland tumors and cancers.
Best regards,
Prof. Cetin Vural, M.D.
ENT & Head and Neck Surgery Specialist
What is a Salivary Gland?
Salivary glands are organs or structures located in our head and neck region that produce a special secretion called saliva, which is then drained into various areas such as the mouth, throat, pharynx, nose, and sinuses through specific ducts.
There are six major (large) salivary glands, three on each side of our face, as well as hundreds of minor (microscopic) salivary glands scattered throughout the mucous membranes. The secretions produced by these glands not only aid in digestion but also provide the necessary moisture and lubrication for the mouth, throat, nasal cavity, and laryngeal spaces, and serve as a defense mechanism against microorganisms that can cause infections.
The major salivary glands include:
- Parotid gland: located in front of the ear
- Submandibular gland: located under the jawbone
- Sublingual gland: located under the tongue
Parotid Salivary Gland
The parotid salivary glands are structures that extend from the front of our earlobes down to the back of the jawline on both sides of our face. The most important detail about these glands is that the facial nerve, which enables us to make facial expressions, passes through the parotid salivary glands.
The facial nerve travels through the bone of the ear and exits the skull through the mastoid process (a bony protrusion just below the ear) before entering the parotid salivary gland to distribute its branches to the facial muscles.
The parotid gland is divided into two anatomical parts in relation to the facial nerve. The part that lies beneath the skin surface and contains the salivary gland is called the superficial lobe of the parotid. The part that lies deeper in the back of the jawbone is called the deep lobe of the parotid.
Submandibular Salivary Gland
This gland is located under the chin on both sides of our jaw and is the second-largest salivary gland after the parotid gland. Its salivary ducts open on both sides of the floor of our mouth just behind our lower front teeth, near the middle line. The marginal mandibular nerve, which is a branch of the facial nerve, passes over the surface of this gland’s capsule.
Sublingual salivary gland:
Named after the term “sublingual,” which means “under the tongue,” this gland is located under and behind the tongue on both sides. This gland, which empties its saliva into the mouth through multiple ducts, is much less likely to develop tumors compared to the parotid and submandibular glands.
Minor salivary glands:
The covering layer of areas such as the mouth, throat, pharynx, and larynx is called mucosa. To keep this mucosa moist, hundreds of microscopic structures, called minor salivary glands, are located in these areas, invisible to the naked eye. These glands produce saliva 24 hours a day and empty it into these spaces, preventing drying of the mucosal surfaces.
What is a salivary gland tumor?
The term “tumor” in Latin means swelling, and it is a term used in medicine to refer to masses that arise from the uncontrolled growth of cells. While any tissue in the body can develop a tumor, salivary glands can also be affected. Tumors can be classified as either benign or malignant. Benign tumors grow more slowly and do not metastasize (spread) to nearby or distant organs. They are usually encapsulated by a thin, membranous covering and do not invade surrounding tissues. They tend to push neighboring tissues aside as they grow, and this growth occurs over months or even years. Benign tumors rarely cause pain, and patients seldom complain of discomfort. If pain is present, it is usually due to indirect causes rather than the tumor itself.
Malignant tumors, on the other hand, grow more rapidly and have the potential to metastasize to nearby lymph nodes and distant organs such as the lungs, liver, brain, and bones. They invade surrounding tissues and disrupt their functions. For example, when they come into contact with neighboring nerves, they can begin to impair their function. Additionally, malignant tumors can cause pain once they reach a certain size. This pain may be due to invasion of structures such as bone or the temporomandibular joint, or it may be caused by direct involvement of nerves that transmit pain signals in the head and face.
In summary, salivary gland tumors;
- Can develop in the major salivary glands located in the head and neck region (such as the parotid gland, submandibular gland, and sublingual gland) or
- In the microscopic salivary glands located within the mucosal layer that lines the nose, sinuses, mouth, throat, and larynx. These tumors can be benign or malignant.
Where can salivary gland tumors occur?
Salivary gland tumors are most commonly found in the parotid gland. Rarely, tumors can also develop in the submandibular gland, and even more rarely in the sublingual glands. Additionally, tumors can develop in areas where minor salivary glands are located, such as the nasal cavity, sinuses, mouth, throat, pharynx, larynx, and the deep regions of the neck known as the parapharyngeal space.
For example, a biopsy taken from a mass in an area like the nose, palate, or base of the tongue may be reported by a pathology specialist as a tumor originating from the salivary gland. In this case, it is thought that the tumor most likely arises from microscopic salivary glands within the lining tissue, also known as the mucosa.
As mentioned above, most salivary gland tumors arise from the parotid gland, especially from the superficial lobe. Rarely, tumors can develop in the deep lobe of the gland. Tumors that arise in the deep lobe are harder to detect and usually appear as a hard lump under the earlobe and behind the lower jaw bone, as compared to tumors that arise in the superficial lobe.
What are the types of salivary gland tumors?
Under this category, some common benign and malignant salivary gland tumors are briefly described.
Benign Tumors
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- Pleomorphic adenoma, also known as mixed tumor, is the most common salivary gland tumor. More than half of salivary gland tumors are benign tumors known as pleomorphic adenomas. They are most frequently found in the parotid gland. In this case, it presents as a swelling in front of or below the ear. Additionally, it can originate from the microscopic salivary glands in areas such as the submandibular salivary gland (swelling under the jaw) or in the palate, throat, and pharynx, causing swelling in those regions.
If left untreated, this tumor carries the risk of transforming into a malignant tumor over the years, a condition known as ‘Carcinoma Ex Pleomorphic Adenoma,’ in which a long-existing, slowly growing mass undergoes a change in behavior and rapidly starts to grow.
- Pleomorphic adenoma, also known as mixed tumor, is the most common salivary gland tumor. More than half of salivary gland tumors are benign tumors known as pleomorphic adenomas. They are most frequently found in the parotid gland. In this case, it presents as a swelling in front of or below the ear. Additionally, it can originate from the microscopic salivary glands in areas such as the submandibular salivary gland (swelling under the jaw) or in the palate, throat, and pharynx, causing swelling in those regions.
MRI image of a benign tumor in the right parotid salivary gland.
- Warthin tumor is the second most common benign salivary gland tumor. It also originates most frequently from the parotid gland. Warthin tumor is more commonly seen in males. This tumor, which mainly arises from the parotid gland, accounts for 10% of all parotid gland tumors. It is believed to be associated with tobacco and smoking habits.Compared to pleomorphic adenoma, this tumor has smoother, round or oval outlines and feels softer to the touch. One characteristic of this tumor is that it can be present in both parotid glands simultaneously.
- Basal cell adenoma is another benign tumor that mostly originates from the parotid gland.
- Oncocytoma is a benign tumor that predominantly arises from the parotid gland but can also occur in other salivary glands. It originates from a type of salivary gland cell called oncocytic cells.In addition to the tumors mentioned above, there are rarer benign tumors such as canalicular adenoma, myoepithelioma, papillary cystadenoma, as well as masses originating from blood vessels such as hemangiomas, lymphangiomas, and salivary gland cysts, all of which can manifest as salivary gland masses.
MRI image of a benign tumor in the left submandibular salivary gland.
Malign Tumors
- Mukoepidermoid carcinoma is the most common cancer of the salivary glands. It generally has different grades: ‘high grade,’ ‘intermediate grade,’ and ‘low grade,’ with high-grade tumors being more aggressive and low-grade tumors having a better prognosis. Patients are usually adults aged 40 and above, but the low-grade type can also occur in younger individuals, particularly in the parotid gland. The tumor can originate from major salivary glands, primarily the parotid gland (salivary gland in front of the ear), as well as from microscopic salivary glands in the nose, mouth, throat, and larynx. The primary treatment is surgical removal, and low-grade tumors often have a high success rate with complete removal. Moderate and high-grade mukoepidermoid tumors may require post-operative radiotherapy and chemotherapy.
- Adenoid cystic carcinoma, also known as adenocystic carcinoma, is a malignant tumor that predominantly arises from microscopic salivary glands. One characteristic of this tumor is its tendency to invade nerves in the affected area. It is more common in individuals of middle age and older, and while it can originate from major salivary glands, it is more frequently found in microscopic salivary glands in the palate, nasal cavity, sinuses, and rarely in the larynx. The primary treatment is surgical removal, and additional radiotherapy and chemotherapy may be necessary if the histopathological examination does not classify the tumor as low-grade.
- Acinic cell carcinoma is a rare malignant salivary gland tumor that often occurs in the parotid gland. In most cases, it is a low-grade tumor and grows slowly, with a lower likelihood of metastasis to the lymph nodes or distant organs. It is more commonly seen in younger individuals, typically in their 20s and 30s, and has a better prognosis compared to other salivary gland cancers. A successful surgery is often sufficient for treatment. The primary treatment is surgical removal, and a complete removal can lead to a favorable outcome for the patient.”Please note that the provided information is for educational purposes only, and it is important to consult with a healthcare professional for accurate diagnosis and appropriate treatment options.
- Salivary duct carcinoma, also known as salivary gland ductal cancer, often originates from the parotid gland (salivary gland in front of the ear). It shares a similar structure to invasive ductal carcinoma seen in the breast. It has been reported that 60% of these tumors are newly developed, while 40% arise from pleomorphic adenoma (a benign salivary gland tumor) and transform into carcinoma (carcinoma ex pleomorphic adenoma).Although predominantly found in the parotid gland, it can rarely occur in other salivary glands as well. Compared to other salivary gland cancers, this tumor is typically of higher grade, meaning it exhibits more aggressive characteristics. The primary treatment for salivary duct carcinoma, if feasible, is surgical removal. Due to the aggressive nature of the tumor, post-operative radiotherapy and chemotherapy are often necessary.
Additionally, the presence of HER2 and Androgen Receptor positivity in the tumor cells, identified through specific pathological staining techniques, may indicate the consideration of targeted therapies in addition to surgery, radiotherapy, and chemotherapy.
- Carcinoma ex pleomorphic adenoma refers to the transformation of a benign salivary gland tumor called pleomorphic adenoma into a malignant tumor after a long period of time. It is known that there is a 5% probability of pleomorphic adenoma transforming into cancer, and this risk is higher in long-standing tumors. Malignant tumors arising from pleomorphic adenoma include salivary duct carcinoma, adenocarcinoma (adenocarcinoma NOS), mucoepidermoid cancer, myoepithelial cancer, and epithelial-myoepithelial cancer. Typically, patients describe the gradual and rapid enlargement of a mass in the parotid region, face, or neck, accompanied by changes in skin color and the onset of pain. The primary treatment is surgical removal.”Please note that the provided information is for educational purposes only, and it is important to consult with a healthcare professional for accurate diagnosis and appropriate treatment options.
Image of our patient’s pleomorphic adenoma that has transformed into salivary gland ductal cancer over a period of 35 years.
MRI images of our patient with carcinoma ex pleomorphic adenoma.
Tomography image of our patient with a tumor in parotid gland.
- Epithelial myoepithelial carcinoma is commonly known as a low-grade malignant tumor with low aggressiveness, and it is most frequently observed in the parotid salivary gland. Typically, it presents as a long-standing, slow-growing mass or swelling. This tumor can either develop as a new tumor or arise from a pleomorphic adenoma. The primary treatment for this tumor is surgery. If there are no indications suggesting a high-grade pathology on pathological examination and the tumor is completely removed through surgery, the likelihood of recurrence is relatively low.
- Lymphoepithelial carcinoma is a rare salivary gland tumor that also predominantly occurs in the parotid salivary gland. It is considered a higher-grade and more aggressive tumor that can metastasize to neck lymph nodes and distant organs. This tumor is believed to be associated with Epstein-Barr virus, similar to nasopharyngeal cancer. The primary treatment for lymphoepithelial carcinoma is surgical removal of the affected salivary gland and neck lymph nodes. Subsequently, treatments such as radiotherapy and chemotherapy may be considered.
- Secretory carcinoma, formerly known as mammary analog secretory carcinoma, is another rare salivary gland tumor. It shares pathological features with secretory carcinoma of the breast. This tumor is most commonly found in the parotid salivary gland and is generally considered a low-grade cancer with relatively low aggressiveness. However, it can rarely metastasize to neck lymph nodes and exhibit high-grade tumor characteristics with distant organ involvement. Nonetheless, in most cases, it follows a more indolent course, and recurrence or relapse is not expected following complete surgical removal.
The difference between salivary gland cancer and salivary gland tumor
Cancer is a term used in medicine to describe certain malignant tumors. By definition, there is no such thing as a benign cancer. However, many types of cancer can be completely treated with modern treatment methods. Tumor, on the other hand, is a broader term that encompasses both benign and malignant growths.
If we emphasize the differences:
Benign tumors grow more slowly. They do not metastasize (spread) to nearby or distant organs. They do not invade surrounding tissues. They typically grow by pushing aside the surrounding tissues to make space for themselves. This growth occurs over months or even years. Benign tumors rarely cause pain, and patients rarely complain of pain. If there is pain, it is usually due to indirect reasons rather than the tumor itself.
Malignant tumors (also called malignant or cancerous) grow more rapidly and have the potential to metastasize to regional lymph nodes and distant organs such as the lungs, liver, brain, or bones. They invade surrounding tissues and develop by disrupting their functions. For example, when they reach adjacent nerves, they begin to affect their functions. For instance, if they invade the facial nerve, they can cause facial paralysis.
Furthermore, malignant tumors can cause pain once they reach a certain size. This pain can be due to the invasion of structures such as bones or the temporomandibular joint, or it can directly affect the nerves responsible for sensitivity and pain in the head and facial area.
What is the difference between a benign and a malignant tumor?
Benign Tumor:
A typical benign salivary gland tumor is characterized by a slowly growing, painless, rubbery mass that has been noticed by the patient for a long period of time. It can be felt as a movable lump between two fingers. These masses can occur in various areas such as the parotid gland, submandibular gland, or palate.
On magnetic resonance imaging (MRI) or computed tomography (CT) scans, benign tumors appear well-defined and do not show invasive features into surrounding tissues. There are no associated symptoms such as facial paralysis, redness or hardness of the skin over the tumor, swelling or enlargement of lymph nodes in the neck.
During surgery, benign tumors are often observed to have well-defined borders, without extending into the surrounding salivary gland or other tissues. They are encapsulated by a thin membrane called a capsule.
Malignant Tumor:
In contrast, malignant tumors are typically characterized by a more rapid development, growing over weeks or months. They can be painful and feel harder, making it more difficult to move between fingers. On magnetic resonance imaging (MRI) or computed tomography (CT) scans, they often appear infiltrative, invading the surrounding tissues, and their boundaries may not be well-defined.
If they are located near the facial nerve, they can cause facial paralysis by impinging on the nerve. If they are close to the skin, they can result in redness, ulceration, or even the formation of sores. When they spread to the lymph nodes in the neck, they can cause swelling on the sides of the neck.
Advanced tumors in the facial and head-neck region can lead to functional impairments in chewing, swallowing, eating, speaking, and other functions.
During surgery, malignant tumors are often observed to be harder than benign tumors, exhibiting invasion into the surrounding tissues, and they may lack a well-defined capsule surrounding them.
What are the causes of salivary gland tumors and who is more likely to be affected?
Especially in the development of malignant salivary gland tumors, smoking, alcohol consumption, and exposure to radiation have been implicated as potential factors. However, clear scientific evidence to support these associations has not been established. The causes of benign tumors are even more uncertain.
Salivary gland tumors can occur at any age and in both genders, including childhood. However, benign tumors, such as pleomorphic adenomas, are more commonly observed in the young and middle-aged population, while malignant tumors are more frequently seen in older individuals. There is no significant difference in tumor frequency between males and females.
What are the symptoms of a parotid salivary gland tumor?
The parotid gland is a gland located in front of and below the ear. Its tumors manifest in this area as swelling, masses, and growth. Typically, they present as a long-standing mass or growth in front of the ear or beneath the earlobe.
This mass often easily moves when pressed between two fingers. The tumor’s growth is usually slow. If the patient delays surgery, the growth of the tumor will become more noticeable over months or years. Tumors originating from the deep lobe may appear as harder-to-detect masses behind the jawbone. Occasionally, they are incidentally discovered on imaging tests such as MRI or CT scans performed for other reasons.
If the tumor is malignant, in addition to swelling, it can be accompanied by pain, facial paralysis, changes in the skin over the tumor surface, ulceration, and swelling of the lymph nodes in the lower parts of the neck.
What are the symptoms of submandibular salivary gland tumors?
The submandibular salivary gland is an organ located under the jaw. Tumors of this gland may present as swelling beneath the jawbone. Most of these tumors are benign and exhibit slow, painless growth. Typically, there is a mass that has been present for months or even years. In the case of benign tumors, growth is usually very slow after the patient becomes aware of the mass.
If the tumor is malignant (salivary gland cancer), it may be firmer and more pronounced compared to benign tumors. Pain can occur due to involvement of surrounding tissues. Over time, changes in the skin covering the tumor may also be observed. If the tumor adheres to the jawbone, it becomes harder and immobile.
Unlike the parotid gland, submandibular gland stones that obstruct the duct are more commonly seen and can cause intermittent swelling, redness, and pain that resolve afterwards. These stones can sometimes lead to salivary gland infection. In such cases, swelling, pain, and redness increase. Antibiotic treatment and the eventual displacement of the stone can provide relief in these findings. In contrast, swelling associated with tumors does not regress or diminish; it progresses and spreads over time. When encountering such swelling, it is advisable to consult an otolaryngologist and allow them to differentiate between the conditions.
Does a parotid tumor cause facial paralysis?
It is highly unlikely for benign parotid tumors (such as pleomorphic adenoma) to cause facial paralysis. However, malignant tumors, as they progress, can invade (disrupt the integrity) the facial nerve that passes through the parotid gland, leading to facial paralysis.
How is the examination for salivary gland tumors performed and which diagnostic tests are applied?
When a suspicion of salivary gland tumor arises, the physician first carefully listens to the patient’s complaints, asks various questions to identify possible accompanying symptoms, and investigates whether there are any notable features related to this condition in the patient’s medical history or family. Subsequently, the examination phase is initiated.
Otorhinolaryngologists generally perform a comprehensive examination of the ear, nose, oral cavity, pharynx, and head and neck, regardless of the reason for the patient’s visit. The tumor is carefully examined through palpation, assessing its size, hardness, mobility, and adherence to surrounding tissues. If the tumor is located in areas such as the nose, mouth, throat, or pharynx, an endoscope, an optical instrument, is used for examination. During these examinations, the presence of enlarged lymph nodes in the neck, decreased facial muscle movement, and weakness are assessed.
Following the physical examination, radiological investigations are performed. Ultrasonography, being the most accessible imaging method, is often the initial choice. The appearance of the mass on the ultrasound is evaluated by the radiologist. Additionally, MRI (magnetic resonance imaging) and CT (computed tomography) provide detailed images, allowing the Otorhinolaryngologist to examine various characteristics related to the tumor in detail.