Approach to chronic pelvic pain (GYN) Quiz: Ace Your Exams

A 33-year-old woman presents to the clinic with a 3-year history of pelvic pain that has been worsening over the past few months. The pain is a constant dull ache in her lower abdomen and sometimes radiates to her lower back and thighs. It worsens significantly during her menstrual period and often begins a week before. She also reports dyspareunia, dyschezia, urinary frequency, bloating, and constipation, especially around menstruation. Over-the-counter analgesics provide minimal relief. She does not have dysuria, hematuria, hematochezia, nausea, fever, abnormal vaginal bleeding or discharge. Her medical and surgical history are unremarkable. Menarche was at age 11. She is sexually active with one male partner, has never been pregnant, and uses condoms consistently for contraception. Family history is significant for a sister with unexplained infertility. Vital signs are within normal limits. Abdominal exam shows diffuse mild lower abdominal tenderness. Pelvic examination reveals posterior cul-de-sac tenderness, nodularity of the uterosacral ligaments, and a right-sided 5 cm mobile, smooth cystic mass. hCG is negative. Which of the following is the most appropriate next step to confirm the likely diagnosis?