Conditions: Salivary Gland Tumors
We have three paired major salivary glands, the parotid, the submandibular, and the sublingual glands, as well as thousands of minor salivary glands. These can develop into benign or cancerous tumors (neoplasms), which are distinctly different from a swelling due to infection or trauma. Diagnosis of a salivary gland neoplasm is often confirmed with a biopsy, and imaging may be included in the evaluation. Treatment options depend on diagnosis, but generally include observation, medication, and surgery. Salivary gland tumors may be categorized according to the specific gland involved or by the type of tumor (based on appearance under a microscope), which generally predicts its behavior.
Evaluation of a salivary gland swelling
Of course, not every salivary gland swelling represents a tumor. Short duration of a swelling, pain, redness, warmth to the overlying skin, and factors predisposing to infection (dry mouth, poor oral hygiene, minimal oral intake, diabetes or other causes of a weakened immune system) suggest infection, rather than tumor/neoplasm. Persistence of a swelling beyond about 7 weeks, the absence of the above infection-suggesting signs and symptoms, a history of previous salivary gland tumor or nearby skin cancer, or characteristics on imaging (ultrasound, CT, MRI), however, may suggest neoplasm. Typically, evaluation of a mass begins with a physician hearing the history of the problem, performing a physical exam, and, when indicated, obtaining imaging. A specialist may be involved at this point, and when tumor/neoplasm is suspected, the next step is typically to obtain an image guided needle biopsy.
Some salivary gland tumors are benign and others are malignant
Benign salivary gland tumors are noncancerous growths that develop in the salivary glands. These tumors are usually slow-growing and, because they are benign, do not spread to other parts of the body. Common types of benign salivary gland tumors include pleomorphic adenoma and Warthin's tumor. Symptoms may include a painless lump in the cheek, neck, or mouth.
Malignant salivary gland tumors are an uncommon type of cancer that can develop in any of the salivary glands located in and around the mouth and throat. These tumors are characterized by abnormal cell growth that, because it is cancer, can spread to other parts of the body if left untreated. Symptoms may include a lump or swelling in the mouth, difficulty swallowing, pain, numbness, or muscle weakness in the face, tongue or neck.
Lymph nodes are not technically part of salivary glands, but do exist within the parotid salivary gland and adjacent to the submandibular salivary glands. Therefore, tumors of the lymph nodes in or near salivary glands may not be readily differentiated from tumors of the salivary glands proper without imaging and/or biopsy.
Lymph nodes themselves can develop a type of cancer called lymphoma, of which there are several types.
Cancer that began elsewhere in the body may spread to lymph nodes in the salivary gland may occur.. An example of this is when a squamous cell carcinoma from the skin around the temple, cheek, or ear spreads to a lymph node within the parotid salivary gland. This is a concerning development because it indicates a more advanced stage of the disease. When cancer cells travel to the lymph nodes around the salivary gland, it signifies a higher risk of the cancer metastasizing to other parts of the body. Lymph node involvement is a crucial factor considered by healthcare providers when determining the appropriate treatment plan for patients with salivary gland cancer.
Salivary gland tumors… by gland:
A tumor in the tail of the parotid gland
Parotid gland tumors
The largest of the salivary glands are the left and right parotid glands, located in front of the ear, extending down just below the earlobe. As there are lymph nodes within the parotid glands, a lump in this area may be a lymph node, or it may be a tumor originating from the parotid gland itself. A benign growth of fat cells (lipoma) is also seen in the parotid gland on occasion.
Large submandibular mass
Submandibular gland tumors
The left and right submandibular glands sit under the jawbone, roughly near the lower canine or premolar tooth. In youth and young adulthood, these glands are not visible, but with age, they normally shift a little lower and show as a small lump under the jaw. A prominence in this area, especially if it is growing or asymmetric should be evaluated.
Glandular cancer from a minor salivary gland on the palate
Sublingual and minor salivary gland tumors
Thousands of minor salivary glands are dispersed throughout the oral cavity and thus tumors can arise from them on virtually any oral surface. The sublingual glands are located under the tongue, just under the surface lining. Tumors of these glands tend to be apparent from within the mouth, and a diagnostic biopsy is taken from oral surface. There are several types of lumps or bumps that can form within the mouth that are not technically neoplasms, such as inflamed areas and scars (fibromas) but when a true neoplastic growth does arise in one of these salivary glands, it has about a 50% chance of being cancerous.
Salivary gland tumors… by tumor type:
Pleomorphic adenoma
Overall the most common type of salivary gland tumor, this benign neoplasm typically grows indefinitely. If neglected over years or decades, a pleomorphic adenoma does have the potential to transform into a cancer (called “carcinoma ex-pleomorphic adenoma), which, becomes more aggressive in growth and can spread to other parts of the body.
Warthin’s tumor (cystadenoma lymphomatosum)
Warthin’s tumor, also known as cystadenoma lymphomatosum, is a benign salivary gland tumor usually found in the parotid gland, and it is not unusual for people to have this this type of tumor on each side. A history of tobacco smoking is a significant risk factor for the development of a Warthin’s tumor.
Lymph node within a salivary gland
Lymph nodes exist within the parotid salivary gland and near the submandibular salivary gland. As with lymph nodes elsewhere, these lymph nodes may be involved with spread of cancer from another site (such as a squamous cell carcinoma from the scalp, temple, face, or ear spreading to a node within the parotid or an oral squamous cell cancer spreading to a node within or adjacent to the submandibular gland), or a tumor originating in the lymph nodes (lymphoma).
Cancer spreading to lymph nodes from a separate site indicates a more advanced stage of the disease. When cancer cells travel to the lymph nodes around the salivary gland, it signifies a higher risk of the cancer metastasizing to other parts of the body, such as additional lymph nodes or other organs such as the lungs.. Lymph node involvement is a crucial factor considered by healthcare providers when determining the appropriate treatment plan for patients with salivary gland cancer. Further diagnostic tests, such as imaging scans or biopsies, may be necessary to assess the extent of cancer spread and to have informed treatment options.
Lymphatic vessels (green lines) and lymph nodes (green balls) exist around and within the parotid salivary gland.
squamous cell carcinoma
Squamous cell carcinoma is a common type of cancer of the skin or lining of the mouth or throat. When squamous cell carcinoma is present in a salivary gland, it has spread from a primary site elsewhere, usually from the nearby skin, but potentially also from the mouth, or throat, and then spreading to a lymph node within the salivary gland.
adenoid cystic carcinoma
Adenoid cystic carcinoma is a type of salivary gland cancer known for its predisposition to spread along nerves. The main tumor mass may be seen and felt, but microscopic tracking along nerves that pass through the area can be extensive.
acinic cell carcinoma
Acinic cell carcinoma is a slow growing salivary gland cancer that is known for its potential to spread to the lungs and grow there so slowly that detection may occur decades after the salivary gland primary tumor has been treated.
Lipoma
A lipoma is a benign tumor of fat tissue, and is generally soft to the touch, painless, and somewhat moveable. These can occur in any fatty tissue of the body, including in the head and neck area. Lipomas are not strictly salivary gland tumors, but may occur so close to a salivary gland tumor as to be a diagnostic consideration when a mass is present where a salivary gland is located. The cancerous analog of a lipoma, called a liposarcoma, is very rare.
Benign lymphoepithelial cysts
These benign cysts are uncommon in the general population, but present in about 5% of HIV patients, nontender one or both sided parotid gland enlargement associated with dry mouth, resulting in dry atrophy of the oral tissues, cavities, and inflammation of the mouth.
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