I know that 'metastatic' means that cancer has spread. I was just diagnosed with retroperineal sarcoma. The doctors are not 100% sure, but this is what they fear. But if it is not primary, where could it have come from. Except from a small pain in my liver, I feel good. The doctors found a lesion behind my bowels. Is this the source? The lesion is not cancerous. I don't know what to believe. I am 42 years old, and I started having this pain about six or seven months ago. I had an ultrasound and an abdominal CT. I now have to have a biopsy and bone scan. What am I to believe?