VM32 - A Minimally Invasive Transabdominal Approach to Presacral Mass Excision

Purpose/Background: Presacral or sacral schwannomas are relatively rare tumors thought to account for only 1 in every 40,000 hospitalizations. These lesions are benign, frequently unifocal, and arise from Schwann cells along the nerve sheath. Lesions are often asymptomatic, but may present with mass effect symptoms (constipation, urinary frequency), sciatica, lower extremity weakness, and para-axial lumbosacral pain. Complete surgical resection is the treatment of choice, with a paucity of literature/media describing/depicting a minimally invasive transabdominal approach to these resections.

Methods/Interventions: Our patient is a 55 year old woman with a history of Multiple Sclerosis who was found to have a presacral tumor seen on previous neurologic imaging studies. During surveillance of the tumor, it was found to have grown to the size of 4.5x5.3x4.3 cm however she remained asymptomatic. She was subsequently referred to our colorectal surgery clinic for consideration of excision of the tumor via transabdominal approach. Here we show a minimally invasive robotic assisted excision of the rare pelvic presacral schwannoma. After obtaining access to the abdomen with 4 robotic trocars aligned diagonally from the right lower quadrant to the left upper quadrant, the patient was placed in steep Trendelenburg with their right side down to allow for adequate visualization of the pelvis. Some adhesions were lysed and the lateral sigmoid was reflected into the left upper quadrant. An incision was made just under the superior hemorrhoidal vessel as our entry point into the mesorectal dissection plane. We continued to dissect and elevate the mesorectum anteriorly until we encountered the encapsulated mass displacing the mesorectum in the right lower portion of the pelvis. We continued to dissect and peel the mesorectum off of the capsule until the most cephalad portion was exposed. Using electrocautery, a linear incision was made along the capsule. Using a combination of gentle traction and electrocautery the tumor was enucleated out of the capsule and lifted out of the pelvis. The capsule was evaluated for any residual tumor or bleeding and found our surgical site to be clear. The tumor was then removed via an EndoCatch bag, leaving the capsule at its origin in its pelvis.

Results/Outcomes: The patient recovered well after surgery and was discharged home the next morning without issue. She has no new or sustained neurologic deficits related to the tumor and has recovered without issue. Final pathology confirmed that the presacral mass was in fact a Schwannoma measuring about 5.5cm with positive S100 and SOX-10 immunostains.

Conclusion/Discussion: Enucleation is the ideal treatment for these lesions so as to minimize chances of neurologic symptoms after surgery and it is not necessary to remove the capsule to help prevent recurrence rates. This case depicts a feasible and safe minimally invasive transabdominal technique to successfully resect a presacral mass.