What should you know about a lump on one side of the neck?

One-sided swelling may be a lymph node responding to infection, a salivary-gland problem, a cyst, a thyroid nodule or another tissue change. Head and neck cancer can present with a neck mass, and lymphoma can involve lymph nodes. Thyroid cancer may cause a lump in the thyroid region. If a mass is found without an obvious primary site, clinicians may investigate Cancer of Unknown Primary. The fact that it is on one side does not show whether it is benign or cancerous.

Note which side and level of the neck is affected, when it appeared, whether it moves, and whether it is tender or growing. Mention recent dental or throat infection, skin inflammation, voice change, swallowing difficulty, tobacco exposure, fever, night sweats or weight change. A clinician may examine the ears, mouth, throat, thyroid and lymph-node groups, then consider imaging or a needle sample. Do not squeeze or puncture the lump.

Seek emergency help for breathing difficulty, inability to swallow liquids or rapidly worsening swelling. Arrange prompt review when a one-sided lump persists, increases, becomes hard or is accompanied by hoarseness, swallowing pain, ongoing throat symptoms, fever, night sweats or unexplained weight loss.

Ask which structure the lump may involve, whether the opposite side feels different, and whether your mouth, throat or thyroid needs targeted assessment. Ask what testing is appropriate, how results will be explained, and which changes should prompt an earlier appointment.