Sarcoma: Fear my partner has sarcoma based on palpation

[PB96]

I write on the behalf of my partner (male, 26).
He has got a very firm, non-mobile (as in not at all), deep located tumor around 1x2-3 cm in his lower left back between the ribs and pelvis in the soft tissues. You really have to push down on the tissues a bit to even notice it.

I first noticed this tumor around 2,5 years ago. Told him to go see his doctor multiple times. but has refused to do so until now.

So.. this thing is small, and have maybe doubled in size in 2,5 years (from about 0,5x1 cm to 1x2-3 cm). Which is not much..
He does have a bit of lower back pain, but then, many people do.

So my questions are..:
- Does anyone else have a sarcoma in the soft tissues of the lower back (not spine)?
- Can it be a sarcoma when it grows so slowly? Have anyone had a tumor for years that turned out to be sarcoma? Had it spread beyond the primary tumor?
- If so, is it likely to be low grade?
- How likely is low grade sarcomas to metastisize? Considering he probably have had this tumor in many years.
- Is bone mets common with sarcomas?
- If it's not a sarcoma, then what can it be?

I've done a lot of research on different studies, and most of them just points to a poor prognosis. Some said that some sarcomas grow very slowly or even stop growing for a time without treatment, but nothing about if they spread anyway.

I'm a young lung cancer surviver myself and still in the follow-ups, hence why I find it hard not to worry about my partner.

[Sara_MHModerator]

Hello and welcome to the forum. Thanks for your question.  I'm glad you've convinced your partner to see a doctor as that is really the only way to know what is going on.  Soft tissue sarcoma is rare but does occur. But please, don't diagnose your partner. I can understand your anxiety given your own out of the ordinary cancer diagnosis.  Soft tissue sarcoma represents 1 percent of all cancers.  Most tumors are rapid growing and can become painful. Your partner's haven't. A synovial cyst is a possibility for what this is. These are harmless. Or an osteoblastoma. These are not cancer. I think it is very wise for talking to him about seeing a doctor to begin the process of determining what your partner has got going on. Don't assume cancer and try to work on your own anxiety surrounding this.  When does he go to the doctor?