A 19-year-old female comes to the physician because of left lower quadrant pain for 2 months. She states that she first noticed the pain 2 months ago but now it seems to be growing worse. She has had no changes in bowel or bladder function. She has no fevers or chills and no nausea, vomiting, or diarrhea. The pain is intermittent and sometimes feels like a dull pressure. Pelvic examination is significant for a left adnexal mass that is mildly tender. Urine hCG is negative. Pelvic ultrasound shows a 6 cm complex left adnexal mass with features consistent with a benign cystic teratoma. Which of the following is the most appropriate next step in management?