MSFinals-1811

A 30-year-old nulliparous woman arrives at the emergency department with a positive home pregnancy test and symptoms of diarrhoea and mild abdominal discomfort that have been present for 6 hours. She has not been using any regular contraception and her last menstrual period was 8 weeks ago. The patient has a history of pelvic inflammatory disease. A transvaginal ultrasound shows a 40mm foetal sac at the ampulla of the fallopian tube without a visible heartbeat, and her serum B-HCG level is 1200 IU/L. What is the definitive indication for surgical management in this case?