Why would a nine year old boy with no history of trauma get blood clots in his legs? Before being diagnosed with the clots he was in the hospital being treated for pneumonia. within 48 hours he developed swelling and pain in his leg and then was diagnosed with DVT. He first had one in the calf and groin of the right leg and was treated with heparin and now has two more inthe left leg. The family does not have a history of blood clotting disorders. the intial blood tests for cancer, lupus and leukemia were negative.