Thanks for the empathy - it is very frustrating. I've researched sarcomas extensively, as well as NETs (neuro-endocrine tumors) and other cancers and conditions that cause slow-growing masses. Indeed, the information I've found is suggestive that I have one of these illnesses - but, as I noted, I need a specialist who will investigate for these rare conditions and pinpoint my problem. Several years ago, I did see a rheumatologist, but he could not make any diagnosis...