This should be evaluated by your son's pediatrician
. While this is likely a minor condition, there are possible problems that would require intervention.
There are many possibilities of what is going on. One possibility is a lipoma. A lipoma is a growth of fat that causes a small ball of tissue underneath the skin. This is a growth, but not a cancer that spreads. While it can be removed there really is no reason to. An ultrasound
can be done to confirm this although a biopsy is the only way to know for sure.
It is possible that this represents a lymph node. A lymph node is a filter point of the blood throughout the body. When enlarged, this can be a sign of infection or a cancer. Cancer of the lymph nodes is known as lymphoma.
There are also other worrisome conditions to be ruled out. Bone cancer or muscle cancer (sarcoma) can also presents as this.
There are other possibilities. Blood clots would be unusual, but possible. Infections (as a ball known as an abscess
) can also cause this but often will cause other problems.
Have your son see his pediatrician. This should be evaluated and the worrisome causes should be ruled out. Good luck!