Laparoscopic Sleeve Gastrectomy for an Obese Patient with Retroperitoneal Schwannoma: A Case Report

The prevalence of obesity has increased markedly across the globe over the past several decades. In parallel, the number of metabolic surgeries has risen sharply in recent years, resulting in a growing incidence of concomitant surgical procedures. Obese individuals have an elevated risk of malignancy, partly due to the chronic inflammation associated with excess adipose tissue. A key clinical question arises: How should surgeons manage unexpected pathology identified during the preoperative evaluation of patients with morbid obesity?

A morbidly obese male patient with a body mass index of 50 underwent evaluation for laparoscopic sleeve gastrectomy (LSG). Preoperative CT and PET-CT revealed a 25-mm retroperitoneal mass adjacent to the left gastric artery. Given the elevated risk of malignancy in obese individuals, it was essential to rule out a malignant process before proceeding with LSG. Thus, we adopted a surgical strategy in which LSG would be performed only if the intraoperative frozen section confirmed the lesion to be benign. The retroperitoneal mass was resected laparoscopically and identified as a benign schwannoma on the intraoperative frozen section, allowing us to proceed with LSG as planned. Retroperitoneal schwannomas are rare and often difficult to diagnose preoperatively, which supports the rationale behind our surgical strategy. To our knowledge, this is the first reported case of concomitant LSG performed following the laparoscopic complete excision of a retroperitoneal schwannoma.

Concomitant procedures performed alongside metabolic surgery may be a viable approach to reduce the overall surgical burden on patients. Given the increased risk of malignancy in morbidly obese individuals, a thorough preoperative evaluation for concomitant malignancies should be considered before bariatric surgery. When an unexpected abdominal pathology is identified on preoperative imaging in obese patients, the intraoperative frozen section analysis of the resected specimen can be a valuable tool to guide surgical decision-making regarding concomitant bariatric surgery.