How common is osteosarcoma? i've had pain in my pelvic region/hip for a while and i'm worried. is it likely to be osteosarcoma or something else?

Uncommon: To have on pelvis , see your doctor to find the cause of your pain , and stop self diagnosing

Get a medical checku: Osteosarcoma is not the first thing you should be thinking as the cause of your pelvic pain(?Where is it located and for how long have you had this pain?). It is rare tumor yet it often presents with swelling and pain on top of a bone, near to a joint. A simple x-ray of the painful area of the bone can tell us if there is any such basis for the pain.But only your doctor can make that decision.