12th May 2024

A 27-year-old woman presents to the emergency department with acute onset of lower abdominal pain on the right side and slight vaginal bleeding.

A 27-year-old woman presents to the emergency department with acute onset of lower abdominal pain on the right side and slight vaginal bleeding. She reports that her last menstrual period was 6 weeks ago and she had a positive home pregnancy test 1 week ago. Her medical history is notable for a previous pelvic inflammatory disease. On examination, she appears pale and has tenderness in the right lower quadrant of her abdomen. A transvaginal ultrasound shows an empty uterine cavity and a mass in the right adnexal region.

Which underlying mechanism is most likely responsible for her clinical presentation?