Growing Pains or Osteosarcoma? Key Symptoms to Know

Because early osteosarcoma symptoms can be very nonspecific, they are sometimes initially attributed to common childhood causes, including “growing pains” ^[1][2]. If you are a parent feeling guilty because you thought your child’s early symptoms were just growing pains, please know that you are not alone, and it is not your fault. Early bone cancer symptoms are notoriously difficult to pinpoint.

Important: The information below describes typical patterns, not strict rules. No single symptom can diagnose or rule out cancer at home. Many other common conditions (like infections, sports injuries, or stress fractures) can cause similar symptoms, and a medical evaluation is the only way to know for sure.

Age of the Child

While there is a lot of overlap, growing pains and osteosarcoma typically affect children at different stages of development:

• Growing Pains: Most common in preschool or elementary-school-aged children ^[3][4]. (Note: The term “growing pains” is just a medical label for a common pattern of harmless, recurring limb discomfort; it does not actually mean normal growth causes the pain.)
• Osteosarcoma: Most frequently presents during the adolescent growth spurt, typically around age 10 to 15 ^[5].
• Keep in mind: Age alone cannot rule either condition in or out. Osteosarcoma can occasionally occur in younger children, and harmless leg pain can happen in teenagers ^[1].

Location (One Side vs. Both Sides)

Where the child feels the pain is an important clue, though not a perfect rule.

• Growing Pains: Usually affect both legs (such as both calves or both thighs) and are felt over a wider area rather than pinpointed to one specific spot ^[6].
• Osteosarcoma: Usually localized to one specific limb (most commonly near the knee, such as the lower thigh bone or upper shin bone, or the upper arm) ^[1][7].

Pain Timing and Impact on Activity

A common myth is that only cancer pain wakes a child from sleep. In reality, both growing pains and osteosarcoma can cause evening and nighttime pain that disrupts sleep ^[6]. The real difference lies in how the pain behaves during the day:

• Growing Pains: The pain comes and goes. During the day, the child will usually have normal physical function and no limitation in their play or activities ^[6][8]. Typical growing pains do not cause a limp ^[6].
• Osteosarcoma: The pain is usually persistent and progressively worsens over time ^[1]. It often hurts more when putting weight on the leg and can cause the child to develop a limp, avoid using the leg, or stop participating in normal activities ^[2][9].

Physical Signs and Swelling

A physical examination by a doctor is an important step in distinguishing between the two.

• Growing Pains: The physical exam is typically normal. The child’s joints will move freely, and there will be no visible swelling ^[6][8].
• Osteosarcoma: As the tumor grows, it may eventually cause physical changes. These can include a lump you can feel, joint swelling, localized tenderness to the touch, and decreased ability to move the joint ^[10][9]. However, the absence of a lump or swelling early on does not rule out a tumor ^[1].

When to Seek Medical Care and Reassurance

Parents often replay the months leading up to a diagnosis, wondering what they missed. Because early osteosarcoma pain can exist before a tumor is large enough to cause swelling, initial medical evaluations and even early X-rays are sometimes completely normal ^[1]. A normal initial X-ray does not always end the evaluation if symptoms continue.

You should promptly contact your child’s doctor for further evaluation if they have:

• Pain that is persistent, localized to one spot, or progressively worsening
• An unexplained limp or reluctance to put weight on a leg
• Swelling, a lump, or restricted movement in a joint
• Pain that consistently interferes with daytime activities

If your child cannot bear weight at all, has severe or rapidly worsening sudden pain, or develops new weakness or numbness, seek urgent medical care.