Review Question - QID 109843

A 25-year-old nulliparous woman presents to her gynecologist complaining of recurrent menstrual pain. She reports a 4-month history of pelvic pain that occurs during her periods. It is more severe than her typical menstrual cramps and sometimes occurs when she is not on her period. She also complains of pain during intercourse. Her periods occur every 28-30 days. Her past medical history is notable for kyphoscoliosis requiring spinal fusion and severe acne rosacea. She takes trans-tretinoin and has a copper intra-uterine device. Her family history is notable for ovarian cancer in her mother and endometrial cancer in her paternal grandmother. Her temperature is 99°F (37.2°C), blood pressure is 120/85 mmHg, pulse is 90/min, and respirations are 16/min. On exam, she appears healthy and is in no acute distress. A bimanual examination demonstrates a normal sized uterus and a tender right adnexal mass. Her intrauterine device is well-positioned. What is the underlying cause of this patient’s condition?