What should you know about small hard lump on leg?

A lump can arise from skin, fat, muscle, a blood vessel, a joint, a healing injury or an enlarged lymph node. Some are harmless and remain stable; others become tender, warm, red or larger. A cancerous soft-tissue mass is one possibility, but a lump does not by itself establish a cancer diagnosis. A clinician will ask when it appeared, whether it moves, whether it hurts and whether there was trauma or infection.

Assessment may include measuring the lump, examining nearby joints and nerves, and arranging ultrasound or other imaging. If the appearance remains concerning, a planned biopsy is safer than trying to remove it without a diagnosis.

Book a clinical appointment if the lump persists, grows, feels fixed, returns after removal or interferes with walking. Note its location and changes, and take a photograph beside a familiar object for comparison. Do not squeeze, puncture or repeatedly massage it. Bring details of recent injury, infection, injections, medicines and any history of cancer. The clinician can decide whether observation, imaging, biopsy or referral is appropriate.

Seek urgent help for a rapidly enlarging painful swelling, a leg that becomes cold or pale, new numbness or weakness, inability to bear weight, heavy bleeding or fever with spreading redness. Contact a clinician soon if the lump is firm and fixed, continues to enlarge, or is accompanied by unexplained weight change, night sweats or persistent tiredness.

What structures could this lump come from? Does it need ultrasound or another scan? If a biopsy is needed, how will it be planned? Which changes should make me call sooner? Could an old injury, infection or medicine explain it?