I had sarcoma (undifferentiated pleomorphic spindle cell) between two ribs possibly caused by radiation after a lumpectomy 18 years previously. I recommend going to a sarcoma center like Mayo, MD Anderson, Dana Farber, or MSK. It’s very important to assemble a team for your care with multiple disciplinary backgrounds. It is extremely rare but increasing due to breast conserving treatment. Ask for genomic testing on the tumor. I’ve had 5 surgeries including bilateral mastectomy because I developed a different cancer in the same breast a few months later. I didn’t truly understand how aggressive this is, I just wanted it out. I know it’s overwhelming and we are walking through a groundbreaking time in this type of cancer.