A painless lump on the side of the neck can have many causes, including benign conditions, infections or more serious diseases. Most commonly, swollen lymph nodes are the result of  infection. Less commonly, it can be cancer.

“Benign causes of a painless mass or neck swelling can include thyroid nodules, swelling of a saliva gland or a reactive lymph node,” said Joshua D. Horton, M.D., head and neck surgical oncologist with the Norton Cancer Institute Head & Neck Tumor Program. “However, it is important to rule out cancer as a cause, especially as HPV-associated cancers, which are seen in younger patients, are becoming more common. Any persistent neck swelling should be taken seriously.”

Causes of lumps in the neck

When an adult presents with a neck mass,  malignancy must be ruled out. Head and neck cancers account for 3% to 4% of all adult cancers diagnosed in the U.S.

Some of the common causes of neck lumps include:

• Inflamed lymph nodes: The most common cause of neck lumps seen in general practice
• Benign tumor: Noncancerous tumors of the neck region such as a benign salivary gland mass, lipoma, hemangioma, or lymphatic malformation
• Thyroid enlargement: Either from a nodule or general enlargement of the thyroid gland called a “goiter”
• Neck cyst: Such as branchial cleft cyst or thyroglossal duct cyst, though these typically occur in younger patients
• Infection: A red or very tender lump that may need antibiotics or surgical drainage if there is an abscess
• Poor dental hygiene: Can lead to swelling and infection in the head and neck areas
• Cancer: Likelihood increases with age, especially for people who smoke or drink alcohol

Other causes of lymph node swelling can be cancers that start in the lymphatic system, known as lymphomas. These can be divided into Hodgkin lymphoma, which often is curable, or non-Hodgkin lymphoma, which has varying prognoses depending on the type.

Sometimes there are nodules on the thyroid. They can be solid or filled with fluid. Thyroid nodules can be large enough to form a visible lump or cause difficulty breathing or swallowing.

Some thyroid nodules are cancerous. Risk factors for thyroid cancer include being assigned female gender at birth, between the ages of 25 and 65 years old and radiation exposure.

A thorough medical history and physical examination can help accurately diagnose the condition leading to the neck mass. The duration and severity of symptoms are key.

Risk factors for neck cancers

If the medical history reveals these risk factors, the likelihood that the mass is malignant increases.

• Tobacco use: Cigarettes, significant secondhand smoke exposure
• Alcohol use: Increases the risk of mouth, throat, and voice box cancer
• Age: Men over age 40 are more likely to develop head and neck cancer.
• HPV: This common infection is associated with an increased risk for neck cancer, especially in younger adults.
• Prior radiation treatment in the head and neck
• Long-term exposure to chemicals: Especially from jobsite exposure in industries such as carpentry, shoe making, furniture construction and metalworking
• EBV: Viral infection associated with nasopharyngeal cancer and neck masses, prevalent in the Asian population

When to refer to a cancer specialist

“If the lump has been present for more than two weeks and there are no signs of infection, such as fever, they should be referred,” Dr Horton said. Other reasons to refer include:

• Strong history of tobacco or alcohol use
• Other head and neck symptoms including change in voice, trouble swallowing, lesion in the mouth, nosebleed, or skin cancer of the head and neck region
• Age and gender in risk groups
• A lump more than 1.5 centimeters in size
• If the lump changes, grows, or develops ulcers
• If the lump is hard and painless

As the incidence of HPV-related oropharyngeal cancers increases, it is important to eliminate this as a source of a new neck mass, and this often involves performing a biopsy. These cancers are caused by HPV and frequently present with primary sites in the tonsil or back of the tongue that stay very small and are only noticed after a neck mass begins to grow. HPV-related head and neck cancers are not associated with a smoking or drinking history.

The Norton Cancer Institute Head & Neck Tumor Program provides a collaborative and multidisciplinary approach to masses on the head, neck and throat, using the latest diagnostic tools, treatments and techniques.