Why does head and neck cancer cause a neck lump?

The head and neck contain many lymph nodes that filter fluid from the mouth, throat, nose, ears, and nearby tissues. A cancer in these regions may grow into nearby structures or travel through lymph channels to a node. The node can enlarge as cells collect there, making a lump under the jaw, along the side of the neck, or above the collarbone. A primary growth can also be felt directly, depending on its location.

A neck lump can also result from infection, inflammation, a cyst, or another non-cancerous change. Examination focuses on its position, size, firmness, movement, skin changes, and how it has changed over time. The clinician may inspect the mouth and throat and decide whether imaging or a tissue sample is appropriate.

Arrange a clinical assessment for a new, persistent, enlarging, firm, or fixed lump, especially when it is not settling after an illness. Note when you first noticed it, whether it is changing, and any related hoarseness, mouth sore, swallowing change, ear pain, or weight change. Do not repeatedly squeeze or massage the area, since this can make it sore and obscure changes.

Seek urgent help for trouble breathing, inability to swallow fluids, rapidly increasing swelling, coughing blood, or severe bleeding. Prompt assessment is also needed for a lump with new weakness, severe pain, high fever, or a rapidly spreading skin change. These symptoms can require immediate support while the cause is investigated.

Ask where the lump appears to arise, what examination or imaging could clarify it, and whether a sample is needed. Ask which mouth, throat, voice, or swallowing changes should be reported quickly and when you should return if the lump does not change.