Overview

The parotid glands are the largest of the three main salivary glands in your body. You have two of them, located just below and in front of each ear, extending down towards your neck. Their main job is to produce saliva, which helps with chewing, swallowing, and digestion.

A "parotid lump" refers to an abnormal growth or swelling within one of these glands. These lumps are caused by an overgrowth of cells. It's important to know that most parotid lumps are benign (non-cancerous). In fact, about 80% of all parotid gland tumours are not cancerous. Malignant (cancerous) tumours in the parotid gland are rare, affecting approximately 1 in 100,000 people each year.

Common types of benign parotid lumps include pleomorphic adenoma (which is the most frequent type) and Warthin's tumour. While benign lumps are not cancerous, some types, like pleomorphic adenomas, can occasionally change over time and become malignant. This is why early assessment and treatment are important.

Besides tumours, other things can cause a lump in the parotid area. These can include swollen lymph nodes (for example, due to infections like tuberculosis), lymphoma (a type of cancer affecting the lymphatic system), or even the spread of cancer from skin malignancies on the face or scalp. Sometimes, blockages caused by salivary gland stones can also lead to swelling and discomfort in the gland.

Symptoms and Causes

Understanding the symptoms and potential causes of a parotid lump can help you know when to seek medical advice. While many lumps are harmless, it's always best to have any new or changing lump checked by a doctor.

Symptoms

The most common symptom of a parotid lump, whether benign or malignant, is a noticeable lump or swelling on one side of the face, typically in front of or below the ear, or on the cheek. Here are some symptoms to be aware of:

• Slowly Enlarging, Painless Mass: This is the most common way benign tumours present. They often grow very slowly over months or years and usually don't cause any pain. Benign lumps typically appear after the age of 40.
• Pain: While many lumps are painless, pain can occur in both benign and malignant tumours. This pain might be due to an infection, bleeding within the lump, or if a cancerous tumour is growing into surrounding tissues.
• Sudden Rapid Growth: If a lump that has been stable for a long time suddenly starts to grow very quickly, this can be a worrying sign. It might suggest that a previously benign tumour, such as a pleomorphic adenoma, has transformed into a more aggressive cancerous form (known as carcinoma ex-pleomorphic adenoma).
• Facial Weakness or Paralysis (Facial Palsy): The facial nerve, which controls the muscles of your face, runs directly through the parotid gland. If a parotid lump causes weakness or paralysis on one side of your face (making it difficult to smile, close your eye, or raise your eyebrow), this is a strong indicator of malignancy and requires urgent medical attention.
• Difficulty Swallowing: A large lump or one that is growing into surrounding areas might make it harder to swallow food or liquids.
• Difficulty Opening the Mouth Widely (Trismus): If the lump affects the muscles or structures involved in jaw movement, you might find it hard to open your mouth fully.
• Facial Numbness: A lump pressing on or invading sensory nerves can lead to numbness in parts of the face.
• Sore or Lesion on the Lump: The presence of an open sore or lesion on the lump itself is more commonly associated with cancerous tumours.
• Facial Asymmetry: The lump can cause one side of your face to look different from the other.

Malignant tumours are more common after the age of 60 and are more likely to cause pain and other concerning symptoms like facial weakness.

Causes

Parotid lumps arise from an abnormal overgrowth of cells within the gland. The specific cause can vary:

• Benign Tumours: Most lumps are benign and result from non-cancerous cell overgrowth. The most common types are pleomorphic adenoma and Warthin's tumour. The exact reason why these benign tumours develop is not fully understood.
• Malignant Transformation: Some benign tumours, particularly pleomorphic adenomas, have the potential to become cancerous over many years if left untreated. This transformation is characterised by a sudden change in growth pattern.
• Malignant Tumours (Cancer): Cancerous parotid tumours are rare. The exact causes of salivary gland cancer are generally unknown. However, certain factors are thought to increase the risk, including:
• • Older Age: The risk of malignant tumours increases with age, especially after 60.
  • Radiation Exposure: Previous exposure to radiation in the head and neck area (for example, from past medical treatments) can be a risk factor.
  • Certain Workplace Exposures: Some specific occupational exposures might slightly increase the risk, though this is rare.
• Other Conditions: Not all lumps are tumours. They can also be caused by:
• • Inflammatory Lymph Nodes: Swollen lymph nodes within or around the parotid gland, often due to infection (such as tuberculosis).
  • Lymphoma: A type of cancer that starts in the lymphatic system.
  • Metastases: This means cancer cells have spread to the parotid gland from a primary cancer elsewhere, often from skin cancers (like squamous cell carcinoma or melanoma) on the face or scalp.
  • Salivary Gland Stones: These small stones can block the ducts that carry saliva, leading to a build-up of saliva and swelling in the gland.

Diagnosis and Investigations

If you notice a parotid lump or experience any concerning symptoms, your GP or dentist will usually be your first point of contact. They will then refer you to a specialist, typically an Ear, Nose, and Throat (ENT) surgeon or a head and neck specialist, for further assessment. If cancer is suspected, you will usually be referred within two weeks.

Diagnosis

The diagnostic process begins with a thorough clinical assessment:

• Medical History: The specialist will ask you detailed questions about your symptoms, including when you first noticed the lump, how it has changed over time, if you have any pain, and if you've experienced any facial weakness or other related symptoms. They will also ask about your general health and any relevant medical history.
• Physical Examination: The specialist will carefully examine your head and neck, paying close attention to the lump itself. They will feel its size, shape, consistency (whether it's soft, firm, or hard), and whether it moves freely or feels fixed to surrounding tissues. They will also check for any signs of facial nerve weakness and examine your mouth and throat.

If cancer is suspected, your case will be discussed by a multidisciplinary team (MDT). This team includes various specialists such as surgeons, oncologists (cancer doctors), radiologists, and pathologists, who work together to decide on the best diagnostic and treatment plan for you.

Investigations

To get a clearer picture of the lump, several investigations may be carried out:

• Imaging Tests: These tests help the doctors see the lump's size, exact location, and whether it's affecting nearby structures.
• • Ultrasound Scan: This is often the first imaging test. It uses sound waves to create images of the lump and can help determine if it's solid or fluid-filled.
  • CT (Computed Tomography) Scan or MRI (Magnetic Resonance Imaging) Scan: These more detailed scans provide comprehensive images of the parotid gland and surrounding areas. They are particularly useful for lumps that feel fixed, if there's a suspicion that the lump extends deep into the gland, or if there is any facial nerve weakness. They help assess the extent of the lump and its relationship to important structures like the facial nerve.
• Biopsy: This involves taking a small sample of cells or tissue from the lump to examine under a microscope. This is crucial for determining if the lump is benign or malignant.
• • Fine Needle Aspiration Cytology (FNAC or FNA): This is a common procedure where a very thin needle is used to collect a sample of cells from the lump. It's usually done with ultrasound guidance to ensure accuracy. The cells are then examined by a pathologist. FNAC is performed for almost all parotid masses.
  • Core Needle Biopsy: If the FNAC results are unclear or if there's a strong suspicion of malignancy or lymphoma, a slightly larger needle may be used to take a small piece of tissue. This provides more material for the pathologist to analyse.

Management and Treatment

The treatment for a parotid lump depends entirely on its cause, whether it's benign or malignant, its size, and your overall health. Early diagnosis and treatment are always important for the best possible outcome.

• Surgery (Parotidectomy): This is the primary treatment for most parotid lumps. A parotidectomy is a surgical procedure to remove the tumour. It is performed under general anaesthetic, meaning you will be asleep during the operation.
• • For well-defined, mobile, and clinically benign lumps, a partial parotidectomy (also known as a superficial parotidectomy) is often performed. This involves removing the tumour along with a small amount of healthy surrounding tissue, while carefully preserving the facial nerve.
  • For larger tumours, those affecting deeper parts of the gland, or if cancer is confirmed or strongly suspected, a total parotidectomy may be necessary.
  • If cancer has spread to nearby bone or muscle, these tissues may also need to be removed during the surgery.
  • Surgery is often recommended even for benign lumps because some can grow very large, cause discomfort, or have a small chance of becoming cancerous over time.
• Radiation Therapy: This treatment uses high-energy X-rays or protons to kill cancer cells. It is typically used for cancerous parotid gland tumours.
• • Radiation therapy is often given after surgery to eliminate any remaining cancer cells and reduce the risk of the cancer returning.
  • In some cases, if surgery is not possible or suitable, radiation therapy may be used as the main treatment.
• Chemotherapy: This involves using powerful drugs to kill cancer cells. Chemotherapy may be used for certain types of parotid gland cancer, especially if it has spread to other parts of the body. The specific drugs and treatment plan are tailored to the type of cancer, its stage, and your general health.
• Specific Treatments for Other Causes:
• • If the lump is due to an infection like tuberculosis, medical treatment with antibiotics will be prescribed.
  • If lymphoma is diagnosed, you will be referred to an oncology or haematology specialist for appropriate cancer treatment.
  • For metastatic skin cancer that has spread to the parotid gland, surgery (superficial or total parotidectomy) may be combined with removal of lymph nodes in the neck (neck dissection).
  • For salivary gland stones causing blockages, treatment might involve removing the stone alone, though this isn't always possible if the stone is deep within the gland or if the gland is significantly diseased.

Prevention

The exact causes of parotid lumps, particularly cancerous ones, are not fully understood. Therefore, specific preventative measures are not well-defined. While certain risk factors for salivary gland cancer have been identified, such as older age, exposure to radiation in the head and neck area, and some workplace exposures, these cannot always be avoided.

The most important "preventative" step is actually early detection. If you notice any new lump or swelling in front of your ear or on your cheek, or experience any of the symptoms mentioned in this leaflet (especially facial weakness, rapid growth, or persistent pain), it is crucial to see your GP or dentist promptly. Early diagnosis and treatment significantly improve the outlook, particularly for malignant conditions, and can prevent benign lumps from growing large or potentially transforming into cancer.

Outlook / Prognosis

The long-term outlook for a parotid lump depends significantly on whether it is benign or malignant, and how early it is diagnosed and treated.

• For Benign Lumps: Most parotid lumps (around 80%) are non-cancerous. These are typically slow-growing and, once surgically removed, are usually cured. Patients generally recover well after surgery. However, it's important to know that some benign tumours, such as pleomorphic adenomas, can occasionally undergo a malignant transformation if left untreated for a very long time. This can lead to a more aggressive cancer with a poorer prognosis. This is a key reason why early assessment and treatment are often recommended even for benign lumps.
• For Malignant Lumps (Cancer): For cancerous parotid tumours, early diagnosis and prompt treatment are crucial for a favourable prognosis. Treatment often involves surgery, sometimes followed by radiation therapy or chemotherapy. The long-term outlook for cancer depends on several factors, including the specific type of cancer cells, how advanced it is (its stage and grade), and your overall health.

If a parotid lump, whether benign or malignant, is left untreated, it can lead to ongoing pain and infection. In rare cases, if a malignant tumour is not treated, it can grow and potentially spread, becoming life-threatening. Regular follow-up appointments with your specialist will be an important part of your long-term care to monitor your recovery and check for any recurrence or new issues.