Everything You Need to Know About Parotid Tumors: Symptoms and Treatment
What is a Parotid Tumor?
A significant portion of tumors that occur in the parotid gland are benign. However, some tumors can be malignant and have the potential to spread to surrounding tissues. Parotid tumors are usually noticed as a slowly growing swelling in front of the ear or under the jaw. Some patients may also experience symptoms such as pain, weakness, or numbness in the facial muscles.
Approximately 70-80% of salivary gland tumors occur in the parotid gland. Of these tumors, approximately 75-80% are benign. However, early diagnosis of malignant tumors is extremely important because serious conditions such as facial nerve involvement, spread to neck lymph nodes, and distant metastasis can develop.
How to Identify a Parotid Tumor?
Parotid tumors often appear as slow-growing masses that initially cause no pain. Patients usually notice a lump in front of the ear when looking in the mirror or while shaving. This lump may gradually grow over weeks or months.
Symptoms that may be seen in parotid tumors include:
- Swelling in front of the ear
- Palpitated mass at the corner of the jaw
- Facial asymmetry
- Discomfort while chewing
- Pain around the ear
- Facial muscle weakness
- Facial paralysis
- Dry mouth
- Swollen lymph nodes in the neck
- Redness or hardening of the skin
Benign tumors are usually slow-growing and painless. Malignant tumors, on the other hand, may show faster growth, pain, adhesion to the skin, and facial nerve involvement. The development of facial paralysis, in particular, is a very important finding in terms of malignancy.
In some patients, the mass in the parotid region may remain the same size for years. However, a detailed evaluation is necessary if there is a sudden onset of growth, pain, or impairment of facial movements.
What are the Causes of Parotid Tumors?
The exact cause of parotid tumors is not always clearly known. However, some environmental, genetic, and lifestyle factors are thought to increase the risk.
Factors that may influence the development of parotid tumors include:
Advanced Age
Parotid tumors are generally more common in middle-aged and older individuals. The risk increases, especially in individuals over 50 years of age.
Smoking
Smoking is a significant risk factor, particularly in the development of Warthin's tumors. Long-term smoking can cause cellular changes in salivary gland tissue.
Radiation Exposure
Individuals who have received radiotherapy to the head and neck region may have an increased risk of developing salivary gland tumors years later.
Genetic Factors
Certain genetic mutations and familial predispositions may play a role in tumor formation.
Chemicals
Long-term exposure to industrial solvents, heavy metals, and certain chemicals has been associated with an increased risk.
Viral Infections
Some studies have indicated that viral infections, such as the Epstein-Barr virus, may be associated with salivary gland tumors.
Chronic Inflammation
Long-term salivary gland infections and chronic inflammatory processes can cause cellular changes.
How Many Types of Parotid Tumors Are There?
Parotid tumors are basically divided into two main groups: benign (non-cancerous) and malignant (cancerous).
Benign Parotid Tumors
Benign tumors do not spread to surrounding tissues and generally grow slowly. However, some benign tumors can undergo malignant transformation over time.
Pleomorphic Adenoma
This is the most common benign tumor of the parotid gland. It usually presents as a slow-growing, painless, and firm mass. If left untreated for many years, there is a risk of malignant transformation.
Pleomorphic adenoma is the most common benign tumor of the salivary glands, particularly occurring in the parotid gland. It is also known as a "mixed tumor" because it contains both epithelial and mesenchymal (stromal) components. This histological diversity has led to the name "pleomorphic." It usually presents as a slow-growing, painless mass that can remain stable for a long time.
Pleomorphic adenoma is most often noticed as a slow-growing, firm, and mobile mass in front of the ear or at the corner of the jaw. Patients usually do not report pain, and facial nerve function is initially completely normal. Therefore, it can grow unnoticed for a long time. It is more common in women and in the 30–60 age range.
The most important clinical feature of the tumor is its continued potential for growth over time, despite being benign. In cases left untreated for many years, both surgical difficulty may increase and, although rare, the risk of malignant transformation may arise. This condition is called "carcinoma ex pleomorphic adenoma" and can lead to a serious clinical picture.
Diagnosis of pleomorphic adenoma begins with clinical examination, but imaging and pathological evaluation are necessary for a definitive diagnosis. Ultrasonography is usually the first-line imaging method and can show the solid structure of the mass. Magnetic resonance imaging (MRI) is very valuable in evaluating the boundaries of the tumor and its relationship with deep tissues.
Fine needle aspiration biopsy (FNAB) plays an important role in diagnosis, but it may sometimes not be sufficient for a definitive differentiation in pleomorphic adenoma. Therefore, a definitive diagnosis is often made with histopathological examination after surgery.
Treatment and Prognosis
The primary treatment for pleomorphic adenoma is surgery. Superficial parotidectomy, usually performed while preserving the facial nerve, is the most frequently used method. Although the tumor may appear encapsulated, it may contain microscopic extensions, so it is important to remove the surrounding parotid tissue along with the mass, rather than just removing the mass itself. Otherwise, the risk of recurrence may increase.
Generally, the prognosis is benign. The recurrence rate after surgery is low, but recurrence can occur in cases of inadequate excision. Long-term follow-up is important, especially in young patients. Furthermore, it is a tumor that should not be completely ignored due to the rare risk of malignant transformation.
Warthin Tumor
This is the second most common benign parotid tumor. It is especially more common in male smokers. In some patients, it can develop in both parotid glands.
Basal Cell Adenoma
A rare benign tumor that usually progresses slowly.
Oncocytoma
One of the rarer benign tumors. It may occur more frequently in older patients.
What are Malignant Parotid Tumors?
Malignant parotid tumors can spread to surrounding tissues, metastasize to lymph nodes, and be life-threatening.
Mucoepidermoid Carcinoma
The most common malignant tumor of the parotid gland. Low-grade types may progress more slowly, while high-grade types can be aggressive.
Adenoid Cystic Carcinoma
A malignant tumor with a high tendency to spread to nerves. There is a long-term risk of distant metastasis.
Acinic Cell Carcinoma
One of the relatively slower-progressing malignant tumors, but there is a risk of recurrence.
Salivary Duct Carcinoma
A highly aggressive malignant tumor. It can spread in the early stages.
Carcinoma ex Pleomorphic Adenoma
This is a malignant tumor that develops from a pre-existing pleomorphic adenoma. It can occur in benign tumors that have been left untreated for a long time.
Lymphoma and Metastatic Tumors
Some systemic diseases or cancers of other organs can metastasize to the parotid gland.
Differences Between Benign and Malignant Parotid Tumors
The differences between benign and malignant parotid tumors are of great importance in terms of clinical approach and treatment planning. Although both groups can present as masses in the parotid gland, the course of the disease, its potential for spread, and clinical behavior differ significantly. Therefore, it is necessary to look at the entire clinical process holistically, not just the physical examination findings. Benign (non-cancerous) parotid tumors generally grow slowly and can remain stable for a long time. In most patients, they do not cause pain and do not affect the facial nerve. The most important characteristics of these tumors are that they do not spread to surrounding tissues and do not metastasize to lymph nodes. However, some benign tumors (especially pleomorphic adenomas) can grow over time if left untreated, making surgery more difficult, or rarely, they can undergo malignant transformation. Malignant (cancerous) parotid tumors, on the other hand, follow a more aggressive clinical course. They generally tend to grow faster and may be accompanied by symptoms such as pain, skin adhesions, or ulceration. One of the most important warning signs is facial paralysis resulting from facial nerve involvement. These tumors can also invade surrounding tissues and spread to cervical lymph nodes. Therefore, early diagnosis of malignant tumors is critical for both survival and functional outcomes. In summary, the distinction between benign and malignant parotid tumors is evaluated based on growth rate, presence of pain, nerve involvement, and spread characteristics. However, a definitive distinction can often be made through imaging techniques and pathological examination.
How to Differentiate Parotid Tumors?
Not every swelling in the parotid region means a tumor. Therefore, differential diagnosis is very important.
Conditions that can be confused with parotid tumors include:
Parotid Gland Infections
Painful swelling may be seen in acute or chronic parotitis.
Lymph Node Enlargements
Neck lymph nodes can sometimes be mistaken for parotid masses.
Sebaceous Cysts
Subcutaneous fat gland-like formations can create a mass sensation in the parotid region.
Lipomas
These are benign tumors originating from fatty tissue.
Branchial Cysts
Congenital neck masses can sometimes be located near the parotid region.
Tuberculosis and Granulomatous Diseases
Some infections can cause a nodular appearance in the parotid gland.
Sjögren's Syndrome
Enlargement and hardening of the salivary glands may occur.
Careful examination, imaging methods, and biopsy are crucial in differential diagnosis.
How is a Parotid Tumor Diagnosed?
Early and accurate diagnosis of parotid tumors is critical for appropriate treatment planning.
Physical Examination
The doctor evaluates the size, hardness, mobility, and facial nerve function of the mass.
Ultrasound
This can assess whether the mass in the parotid gland is cystic or solid. Neck lymph nodes can also be examined.
Magnetic Resonance Imaging (MRI)
MRI imaging is very useful in evaluating the tumor's deep tissue involvement and its connection to the facial nerve.
Computed Tomography (CT)
This can be used in cases of suspected bone involvement or advanced disease.
Fine Needle Aspiration Biopsy (FNAB)
This is one of the most frequently used diagnostic methods for parotid tumors. A sample of cells is taken using a thin needle and subjected to pathological examination.
Tru-Cut Biopsy
In some cases, a larger tissue sample may be required.
PET-CT
Can be used to investigate metastases in malignant tumors.
A definitive diagnosis is often made by pathological examination of the tissue removed after surgery.
How are Parotid Tumors Treated?
The primary treatment for parotid tumors is surgery. The treatment plan is determined by whether the tumor is benign or malignant, its size, and the extent of its spread.
Surgical Treatment
Superficial Parotidectomy
This is the removal of tumors in the superficial part of the parotid gland. It is one of the most frequently performed surgeries.
Total Parotidectomy
This involves the removal of the entire parotid gland. It is more frequently performed in malignant tumors.
Neck Dissection
If there is lymph node involvement, the lymph nodes in the neck may also be removed.
Preservation of the Facial Nerve
Since the facial nerve passes through the parotid gland, preserving the facial nerve during surgery is extremely important. The risk of permanent facial paralysis can be reduced in surgeries performed by experienced surgeons.
In some advanced malignant tumors, if the tumor has affected the facial nerve, it may be necessary to remove a portion of the nerve.
Possible Complications After Parotid Surgery
Some complications may develop after parotid surgery.
Transient Facial Paralysis
Temporary facial muscle weakness may occur after surgery. Most patients recover over time.
Permanent Facial Paralysis
Rare, but the risk may increase, especially in malignant tumors.
Frey Syndrome
Sweating and redness in the surgical area when eating.
Hematoma
Blood accumulation may occur in the surgical area.
Infection
Surgical site infection is rare.
Salivary Fistula
May occur due to saliva leaking under the skin.
Additional Treatments in Parotid Cancer
In some malignant tumors, surgery alone may not be sufficient.
Radiotherapy
Can be applied in high-grade malignant tumors, in the presence of positive surgical margins, or in patients with nerve involvement.
Chemotherapy
Can be used in advanced or metastatic disease, but may have limited effectiveness in parotid cancer.
Targeted Therapies
Molecular targeted therapies can be used in some specific tumor types.
Follow-up Process in Parotid Tumors
Regular follow-up after treatment is of great importance. There is a risk of recurrence, especially in malignant tumors.
During the follow-up process:
- Physical examination
- Ultrasonography
- MRI imaging
- Neck evaluation
- PET-CT scans may be performed if necessary.
More frequent check-ups are recommended in the first few years. Long-term follow-up is necessary because recurrence can occur even years later in some malignant tumors.
Can Parotid Tumors Be Prevented?
Completely preventing parotid tumors is not always possible, but avoiding certain risk factors can be protective.
Recommendations for prevention:
- Quitting smoking
- Avoiding exposure to chemicals
- Regular health checkups
- Not neglecting swellings in the head and neck area
- Seeking expert evaluation for long-term salivary gland complaints
Early diagnosis significantly increases the success rate of treatment in both benign and malignant tumors.
Parotid tumors are important diseases originating from the salivary glands, which can be benign or malignant. Painless swellings developing in front of the ear are the most common reason for seeking medical attention. Masses that grow rapidly, are painful, or are accompanied by facial paralysis should be carefully evaluated for malignancy.
Ultrasound, MRI imaging, and fine-needle biopsy play an important role in diagnosis. Surgery forms the basis of treatment. The success rate is quite high in patients diagnosed early. Therefore, it is crucial that any mass detected in the parotid region be evaluated by an ENT specialist.
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Murat Enoz, MD, Otorhinolaryngology, Head and Neck Surgeon
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