There are many causes of lumps in the neck. The most frequently seen lumps or swellings are enlarged lymph nodes. These can be caused by bacterial or viral infections, cancer (malignancy), or other rare causes.
Enlargement of the salivary glands under the jaw may be caused by infection or cancer. Lumps in the muscles of the neck -- almost always in the front of the neck -- are caused by injury or torticollis. Lumps in the skin or just below the skin are often caused by cysts, including sebaceous cysts.
The thyroid gland may also produce a lump, multiple lumps, or swelling in the neck as a result of thyroid disease or cancer. Most cancers of the thyroid gland are extremely slow-growing and often curable by surgery, even if they have been present for several years.
All neck lumps in children and adults should be checked immediately. In children, most neck lumps are caused by treatable infections. However, treatment should start quickly to prevent complications or the spread of infection.