This 39-years old woman presented with manubrio-sternal pain. She had met many doctors with no respite. One surgeon thought of an osteoid osteoma and sent for an MRI., which revealed no abnormal focal enhancement. Since the MRI showed an arthropathy, I did a CT guided biopsy, which was negative for everything.
Based on all this, the physician eventually labelled her as CNO and treated her. She responded well.