My son is 23 and had an incidental finding of a cyst on his thymus. He has been referred to an ENT for treatment. What is the likelihood of this being cancer? He has had some anxiety issues of late, feels like his head is full , strange feeling in his chest, a little difficulty swallowing, hand tremors, and some mild transient muscle weakness in the legs, all of which could be associated with his stress level. Thanks for your opinion.