My 13 yo son has a lump about 6 inches from his wrist on the underneath of his forearm.  I just noticed it today, but he tells me its been there for over a year.  He also said it has gotten bigger.  It feels like a solid bump, but moves around within a small space.  It has a very, very, VERY slight reddish appearance. His yearly checkup is next week.  I am just worried that I should get it looked at now.  Can you give me an idea if I should go now or wait; i.e. should I worry?
Hi! Thanks for writing to us sharing your sons' problem of the enlarging solid slightly mobile lump on the forearm! If I were your primary physician and had you presented him to me with this problem, I would like to consider following possibilities, as per my experience of ultrasound, CT scan and needle biopsies