Signs and Symptoms of Osteosarcoma

Osteosarcomas are usually found because of the symptoms they cause.

Pain and swelling

Pain in the affected bone (usually around the knee or in the upper arm) is the most common symptom of osteosarcoma. At first, the pain might not be constant and may be worse at night. The pain often increases with activity and may result in a limp if the tumor is in a leg bone.

Swelling in the area is another common symptom, although it may not occur until several weeks after the pain starts. Depending on where the tumor is, it may be possible to feel a lump or mass.

Limb pain and/or swelling are very common in normal, active children and teens. They are much more likely to be caused by normal bumps and bruises, so they might not prompt a doctor visit right away. This can delay a diagnosis. If your child has these symptoms and they do not go away within a few weeks (or they get worse), see a doctor so that the cause can be found and treated, if needed.

These symptoms are less common in adults, so they should be a sign to see a doctor even sooner.

Bone fractures (breaks)

Although osteosarcoma might weaken the bone it develops in, the bones often do not break. Telangiectatic osteosarcomas, which are rare, tend to weaken bones more than other forms of osteosarcoma and are more likely to cause a fracture at the tumor site.

People with a fracture next to or through an osteosarcoma often describe a limb that was sore for a few months and suddenly became very painful when the fracture occurred.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: April 18, 2014 Last Revised: January 27, 2016

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