Incidental detection of gastrointestinal stromal tumors during laparoscopic sleeve gastrectomy. What to do?

Introduction: We evaluated and characterized the incidental GISTs during laparoscopic sleeve gastrectomy in our clinic.

Methods: All GISTs identified during laparoscopic sleeve gastrectomy between January 2015 and December 2017 were evaluated. Typical demographic, clinicopathologic, treatment, location, resection margins, immunohistochemistry (CD 34, CD 117, ASMA, desmin and S100) and criteria for oncological aggressiveness (tumor size, number of mitoses, presence or absence of tumor necrosis) data were recorded.

Results: Within the 800 bariatric surgeries at our institution, 7 GISTs were identified (0.87%). The median age of the patients was 32 years (age range: 24-42 years). The mean BMI was found to be 40.66 kg/m2 (range: 35-44 kg/m2). All GIST cases were found in the stomach samples. All tumors were not larger than 20 mm. All tumors were found close to the greater curvature of the stomach; in five cases, tumors were located in a single focus, while in 1 case, it was located both in the corpus and fundus. CD117 and CD34 were found to be positive in the pathological examination of all parts. In addition, desmin, smooth muscle actin (SMA) and S-100 were also positively stained. No complications or mortality were observed in this series.

Conclusion: Tumor resection with a negative surgical margin may be considered complete oncologic treatment in case of presence of very low or low risk classification of postoperative GIST recurrence. After GIST resection, all patients should remain under long-term postoperative care.

Key Words: Bariatric surgery, Incidental gastrointestinal stromal tumors, Obesity, Sleeve gastrectomy.