Renal Remnant Presenting as a Large Retroperitoneal Mass in a Teenage Girl

Background: Adolescents commonly present with a symptomatic pelvic mass. The vast majority of these masses are benign and gynecological in nature. Nonetheless, it is important to consider less common etiologies including retroperitoneal and enteric cysts. Case: A 17-year-old female patient with chronic pelvic pain due to a large 9-cm cystic pelvic mass underwent laparoscopy. Operative findings indicated a retroperitoneal mass, which was excised in a minimally invasive fashion. Final pathology was suggestive of a remnant of a developmental renal anomaly. Summary and Conclusion: This case highlights the importance of a broad differential when considering etiologies of a cystic pelvic mass. Clinical diagnosis and management are often challenging. Therefore, it is important to increase awareness of this diagnosis within the gynecological community.