My fiance (35) also began having lumps in his legs and arms that we later found out to be blood clots. After 1 year of tests and an angiogram, they diagnosed "Polyarteritis Nodosa". You may want to look into that disease. It is an autoimmune disease where the body attacks itself, in this case being the blood vessels and arteries. His treatment has been prednisone and chemotherapy. It also has effected his lungs by the way. The prognosis is not good. Cooincidently it effects primarly men in their 30's to 40's.