Background Surgical management of giant paratubal cysts can be challenging in the pediatric and adolescent population. Larger adnexal masses can heighten suspicion for malignancy, placing the ovary at risk of unwarranted removal, and larger masses sometimes necessitate larger surgical incisions which can increase postoperative pain and delay return to school and regular activities. We present the evaluation and management of a giant paratubal cyst containing 16 l of fluid in an adolescent, using a mini-laparotomy approach. Case presentation A 16-year-old patient presented with 1-month history of worsening nausea and increasing abdominal girth. Abdominal imaging revealed a 42-cm adnexal mass. A modified drainage technique with a mini-laparotomy incision was utilized, thereby preventing tumor spill while minimizing size of the surgical incision. Postoperative recovery was complicated by prolonged nausea, but the patient was discharged home 2 days after surgery and returned to school the following week. Conclusion This case illustrates that giant adnexal masses can be managed using a mini-laparotomy approach, thereby expediting return to regular activities.