Incidental gastric micro-GISTs in sleeve gastrectomy: Incidence and intraoperative management in a single-center cohort.

Abstract

456 Background: Incidental gastrointestinal stromal tumors (GISTs) are increasingly recognized during bariatric surgery. The true frequency in sleeve gastrectomy (LSG) and how to manage lesions without derailing the bariatric plan remain practical questions. Methods: Single-center retrospective cohort of consecutive LSG specimens (2019–2023). We prespecified an intra-operative decision rule: systematic gastric inspection; no biopsy/aspiration; proceed to negative-margin wedge only if it does not materially alter the bariatric plan; if alteration is required, modify/convert only with prior consent and MDT agreement; otherwise defer and stage resection. A uniform pathology protocol (CD117/CD34/DOG1, mitotic index, necrosis) was applied. Incidence was estimated with 95% CIs. Results: Among 1,200 LSG specimens, 19 incidental gastric GISTs were identified (1.58%; 95% CI 1.02–2.46). All were unifocal micro-GISTs (0.2–0.6 cm), spindle-predominant, with non-significant mitoses and no necrosis. Immunohistochemistry was uniformly CD117/CD34/DOG1 positive. R0 resection was achieved within the sleeve specimen or with a simple wedge, without material change to the bariatric plan and without intra-operative biopsy/aspiration. Conclusions: In a high-volume bariatric surgical program, incidental micro-GISTs possess significant clinical implications yet can be effectively managed through negative-margin resection incorporated into LSG, while concurrently avoiding intra-operative biopsy or aspiration procedures that may pose a risk of tumor rupture and necessitate escalation to imatinib therapy. We advocate for a practice-oriented workflow (systematic intra-operative assessment → evaluation of resectability and impact triage → execution of wedge resection with an anticipated sleeve versus modification of the surgical plan with prior informed consent versus a decision to abort the procedure for collaborative decision-making), which is in alignment with current evidence and can be promptly implemented across various bariatric surgical pathways. Cohort summary (incidental micro-GISTs in LSG). Variable Value Total LSG specimens 1,200 Incidental GISTs (n) 19 Incidence (%, 95% CI) 1.58 (1.02–2.46) Tumor size, cm (range; mean ± SD) 0.2–0.6; ~0.41 ± 0.14 Histology Spindle predominant; occasional mixed Mitotic index Non-significant Necrosis Absent IHC CD117+, CD34+, DOG1+ (100%) Change in bariatric plan None material Intra-op biopsy/aspiration Not performed