Lipoma or Liposarcoma? Robotic Resection of a Retroperitoneal Mass

Abstract

Study Objective Demonstrate robotic-assisted resection of a large retroperitoneal lipomatous mass. Design Surgical video Setting Tertiary-care operating room using DaVinci Xi system with four 8 mm trocars, and a 12 mm assistant port. Patients or Participants A 48-year-old female with a multi-fibroid uterus and seven centimeter lipomatous mass in her right hemipelvis Interventions The patient underwent robotic-assisted excision of the right retroperitoneal mass, total hysterectomy, right salpingo-oophorectomy, left salpingectomy, and cystoscopy. Measurements and Main Results Although superficial lipomas are common and most likely benign, retroperitoneal lipomatous tumors are rare. Tumors greater than ten centimeters have a higher malignant potential and are typically found in the deep retroperitoneal space. Robotic-assisted laparoscopy revealed a large lipomatous mass in the right retroperitoneal space consistent with radiographic imaging. The surgeon divided the round ligament and extended the incision parallel to the infundibulopelvic ligament to enter the right retroperitoneum. He then carefully dissected and resected the lipomatous tumor from the pararectal space and performed the remainder of the procedures without complication. Benign lipomas and low grade liposarcoma are difficult to differentiate. The latter has a high rate of local recurrence if incompletely resected, therefore complete resection should be the surgical goal. Pathology revealed partially encapsulated mature adipose tissue consistent with lipoma with negative fluorescent in situ hybridization (FISH) analysis using a dual color MDM2/CEN12 probe set confirming the likely benign behavior of the mass. Conclusion Retroperitoneal lipomatous tumors are rare. Distinguishing between lipomas and liposarcomas is a diagnostic challenge both radiographically and intraoperatively. Confirmatory histopathology, and often molecular pathology, is necessary for the final diagnosis. Knowledge of the pathology of retroperitoneal lipomatous masses and the related surgical anatomy and goals are imperative to optimal management.