Soft tissue sarcoma?

Hi, I’m new to here but off for a scan of my lower leg on Thursday. Just over a week ago I noticed a hard, immovable lump just to the side of my shin on left leg. I called doc for advice but was very quickly booked to see someone the next morning. Next day the doc examined it for about 20 seconds before saying he’d arrange a scan and he didn’t really say much else  

That was last week and now I have an appt on Thursday afternoon. 

Its a hard lump which seems to have appeared quickly and is around 2 inches in length but the main concern is that it appears to be deeply embedded in the tissue. Clearly I’m worried but has anyone on here had anything similar in symptoms which has turned out to be completely harmless? 

Thanks.