Does cancer of unknown primary cause new lump or swelling?

A new mass does not identify its cause. Infection, inflammation, a cyst, injury, and other non-cancerous conditions can also produce a lump or swollen area.

Cancer of unknown primary is diagnosed when cancer cells are found in the body but their original site cannot be identified after assessment. A lump may represent an enlarged lymph node or abnormal tissue at a place where those cells have settled. Its body location and the cell type found in a sample can offer clues about where the cancer began.

Clinicians assess more than size. They consider how long the area has been present, whether it is growing, its texture and mobility, changes in the skin above it, and symptoms elsewhere. A physical examination may be followed by imaging, blood tests, or tissue sampling depending on these findings.

Record the lump's location, when you first noticed it, whether it changes or grows, and whether it is tender. Mention fever, night sweats, skin changes, recent infection or injury, appetite changes, and unplanned weight loss. A photo can document visible change, but it does not replace examination.

Avoid pressing, puncturing, or trying to drain the area. Arrange a clinical review if it does not settle, is enlarging, is firm or fixed, or has no clear explanation. Testing is selected according to the site and examination rather than using the same sequence for every lump.

Get urgent help if swelling causes trouble breathing or swallowing, rapidly affects the face or neck, or comes with fainting, confusion, severe pain, or a very unwell feeling. Prompt assessment is also appropriate for a growing unexplained mass, broken or bleeding skin over it, new weakness in a nearby limb, or swelling that interferes with movement.

Ask which tissues or lymph nodes are involved, what imaging can show, whether a sample is needed, and how its results could narrow the possible origin. Confirm when results are expected and who to contact if the swelling changes while you wait.