Should Lipoma in the Psoas Muscle Be Removed?

During a routine scan before prostate surgery, a tumor showed up in my husband's right psoas muscle which could be a lipoma or a liposarcoma. He is going for an MRI tomorrow for further study. Does it have to be removed if it is a lipoma? If this is determined to be cancerous, what kind of surgery is done to remove it. My husband is a stroke survivor and would have to be off plavix, etc. Please advise