My 17 year old son appears to have a tumour on his shin. 2 months ago his 15 year old brother was diagnosed with an osteochondroma - benign tumour that looks like a marble on his knee. He's still awaiting a specialist appt - for cursory monitoring. He had an X-ray, ct and mri so they were very thorough. My 17 year old has been experiencing pain and limping when running, walking upstairs and sometimes walking. He's been doing a lot of running without rest days and I assumed it was shin splints. Upon seeing a physio she said there's a lump on his bone which was unusual to her. She didn't feel it was muscular and suggested he might want to see his gp. My son said it was more of an afterthought and she didn't appear concerned. For a week or so he continued to rest his legs and do her suggested exercises - with no change to the bone. The lump cannot be seen but can be felt along his shin. 
We visited the gp who was excellent and said he needed an urgent X-ray which he had last week. The gp rang him the next day and said he needs an urgent referral to a bone specialist - bone cancer centre (not our local hospital), an urgent mri and urgent bloods. My 17 year old took the call alone and was shell shocked. We had no info. 
We spoke to the gp the next day and they explained the radiographer description is of concern - the tumour bone structure differed to the bone structure in other parts of the leg. 
I'm sick with worry. My 15 year old had tests over a couple of months whilst the process for my 17 year old is very different. He's had his bloods done, the next day, awaiting results. I'll be chasing up the appointment in a couple of days as per the clinical pathway guidance. 
My 15 year old is having his bloods monitored as he's had a few incidents of dizziness and collapsing and his lymphocytes were pretty low around a month ago. I'm now wondering whether his osteochondroma isn't as innocent as it appears. 
My two fit and healthy boys are now possibly experiencing illness, possibly serious illness and I'm beside myself. 
Any advice or reassurance will be gladly welcomed! Thank you for reading this far....