Dental-floss traction-assisted endoscopic full-thickness resection of a gastrointestinal exophytic tumor: A case report

Abstract

Exophytic gastrointestinal tumors, including gastrointestinal stromal tumors and leiomyomas, present unique technical challenges due to their predominantly outward growth pattern. Conventional endoscopic techniques, such as endoscopic mucosal resection and endoscopic submucosal dissection, often have limitations in achieving complete resection in these cases, and surgical approaches are therefore frequently required. We report a case of an exophytic gastric tumor successfully treated using dental floss-assisted traction combined with endoscopic full-thickness resection. This approach improved lesion exposure by enabling active repositioning of the extraluminal component into the gastric lumen, thereby enhancing procedural controllability. This case highlights a practical technical strategy for managing selected exophytic lesions and suggests that endoscopic resection may represent a feasible minimally invasive alternative in appropriately selected patients.

Introduction

Gastrointestinal exophytic tumors (GETs) are defined as lesions of intramural origin with more than 50% of the mass extending beyond the serosal surface. ¹ Typical examples include gastrointestinal stromal tumors (GISTs), leiomyomas, and schwannomas.^2,3 Although the proportion of exophytic tumors in gastrointestinal tumors has not been reported accurately, exophytic tumors account for more than 50% of small intestinal GIST and gastric schwannomas,^4,5 indicating that GETs are not rare. Owing to their predominant extraluminal extension and relatively large size at diagnosis, GETs are typically managed by laparoscopic resection, laparoendoscopic surgery, or endoscopic full-thickness resection (EFTR),^6–8 as conventional endoscopic techniques often have limited therapeutic efficacy. Although floss traction has been previously described in EFTR procedures,^9,10 its application to facilitate exposure of predominantly exophytic gastric lesions remains limited. In this report, we present a case of EFTR of a GET using dental floss-assisted traction and discuss dental floss traction-assisted EFTR as a potential alternative approach for the management of GETs.

Case presentation

A 36-year-old woman presented with a 4-year history of postprandial epigastric discomfort. Esophagogastroduodenoscopy (EGD) at an outside facility in February 2021 identified a 1.0 cm submucosal lesion in the body of the stomach, without further evaluation. Follow-up EGD in April 2025 showed enlargement to ~1.5 × 2.0 cm. Endoscopic ultrasonography (EUS) demonstrated a 19 × 11 mm homogeneous, hypoechoic lesion arising from the muscularis propria, highly suggestive of a GIST (Figure 1(a) and (b)). Abdominal contrast-enhanced computed tomography (CT) confirmed an extraluminally growing submucosal tumor without lymphatic metastasis (Figure 1(c) and (d)). A diagnosis of GET was considered. Given the patient’s postprandial epigastric discomfort, intervention was requested, and endoscopic resection was considered as the initial treatment approach. However, the lesion exhibited a predominantly exophytic growth pattern on EUS and contrast-enhanced CT, making conventional submucosal dissection or tunneling techniques technically challenging due to limited exposure. Following a detailed discussion, the patient and endoscopist elected to proceed with a dental floss-assisted traction EFTR to achieve en bloc resection under direct visualization.

Figure 1.

Preoperative evaluation of the GET. (a, b) Endoscopic ultrasonography revealed a 19 × 11 mm homogeneous, hypoechoic submucosal lesion on the greater curvature of the gastric body arising from the muscularis propria. (c, d) Contrast-enhanced CT demonstrated an extraluminal growing submucosal mass in the gastric body (red arrows) without evidence of lymph node metastasis.

Under general anesthesia with endotracheal intubation, endoscopy revealed a 1.5 cm submucosal tumor in the upper portion of the greater curvature. The lesion was firm on probing, with intact overlying mucosa. A circumferential incision was made using a Boston knife along the cranial margin of the lesion and the muscular layer, exposing a tumor extending to the peritoneal cavity. The endoscope was then withdrawn, a titanium clip with a dental floss ligature was prepared, and the endoscope was reinserted. The lesion was grasped with the titanium clip, the external dental floss was secured with hemostatic forceps, and traction was applied to fully expose the tumor. Full-thickness dissection was subsequently performed. After hemostasis, the defect was closed using one three-arm clip and 10 soft tissue clips. Carbon dioxide insufflation was used throughout the procedure, and the pneumoperitoneum was decompressed using a disposable puncture needle after artificial perforation during EFTR. The procedure was completed uneventfully in 45 min, and the specimen was retrieved for pathological examination (Figure 2(a)–(f)).

Figure 2.

Endoscopic resection of the GET. (a) Preoperative endoscopic view of the lesion. (b) Circumferential incision at the proximal side of the tumor and dissection along the muscular layer to expose the lesion. (c) Application of a dental floss-traction tissue clip to elevate the tumor and enhance visualization of the operative field. (d) Post-EFTR view showing intraperitoneal liver tissue visible through the gastric lumen. (e) Closure of the full-thickness defect using tissue clips. (f) Retrieval of the completely resected tumor through the cardia-esophagus-oral cavity under dental floss traction. (g) Intact resected GET. (h, i) Gastrointestinal stromal tumor showing <5/50 HPF, without necrosis or invasive growth.

Postoperatively, the patient experienced epigastric pain without hematemesis or melena and received intravenous piperacillin–tazobactam for 3 days for infection prophylaxis, fasting for 72 h, ECG monitoring, hemostatic therapy, acid suppression, and nutritional support. She was discharged on postoperative day 3. Histopathological examination confirmed a GIST with R0 resection, an intact pseudocapsule, and no evidence of tumor rupture. The tumor was classified as very low risk (2008 modified NIH recurrence risk grading system) and one group (WHO prognostic group; Figure 2(g)–(i)). At 1-year follow-up, EGD revealed a postoperative scar on the greater curvature of the upper gastric body, with smooth surrounding mucosa and a residual titanium clip, without evidence of tumor recurrence or residual lesion (Figure 3(a)). The clinical timeline for this patient is shown in Figure 3(b).

Figure 3.

Patient follow-up EGD findings and clinical timeline. (a) EGD at 1-year follow-up demonstrated a postoperative scar on the greater curvature of the upper gastric body, with smooth surrounding mucosa and a residual titanium clip, without evidence of tumor recurrence or residual lesion. (b) Timeline of the patient’s clinical course.

Discussion

GETs typically extend beyond the gastrointestinal lumen and often present with subtle or nonspecific symptoms. Because endoscopy visualizes only the mucosal surface, diagnosis frequently relies on cross-sectional imaging or EUS.^11,12 Compared with intraluminal lesions, the safety of endoscopic resection for exophytic tumors remains a concern, as these lesions are predominantly extraluminal, have indistinct borders, and offer limited operative space. ¹³ In this case, preoperative contrast-enhanced CT and EUS were performed to delineate tumor growth pattern and exclude metastasis or intralesional ulceration. Dental floss traction was then employed to optimize exposure of the operative field, enabling complete removal of the lesion by EFTR.

GETs represent a morphological growth pattern rather than a specific pathological entity, and their histologic spectrum is diverse. Most exophytic lesions, such as GISTs, leiomyomas, and schwannomas, are benign or indolent. Management must be individualized based on tumor size, location, and malignant potential. Current evidence suggests that surveillance is generally appropriate for asymptomatic subepithelial lesions <2 cm in diameter or those lacking high-risk features, whereas endoscopic or surgical resection may be considered for symptomatic lesions or those with an uncertain diagnosis. Endoscopic resection is considered appropriate for GISTs <2 cm and for selected low-risk GISTs measuring 2–5 cm, while surgical resection is typically recommended for tumors >5 cm.^6,7,14

Endoscopic resection of GETs requires careful preoperative evaluation, including exclusion of lymph node metastasis and assessment of whether complete resection can be safely achieved with an acceptable risk of residual disease or recurrence. When histologic confirmation is necessary, EUS-guided needle sampling or mucosal-incision-assisted biopsy may be performed prior to intervention.^15,16 Currently, the main endoscopic approaches for GETs include EFTR and submucosal tunnel endoscopic resection for extraluminal tumors (STER-ET).^17,18 Compared with EFTR, STER-ET preserves the overlying mucosa and avoids intentional perforation, but its application is limited by tumor size and location, and it requires advanced endoscopic expertise. ¹⁷ EFTR allows true full-thickness resection, achieving near 99% en bloc resection rates with a low complication profile; abdominal infection has been reported only rarely. ¹⁹ As EFTR involves intentional creation of a full-thickness defect, secure closure of the mucosal and muscular layers with tissue clips is critical to prevent pneumoperitoneum and postoperative discomfort. ²⁰

Adequate traction is essential for optimizing the endoscopic operative field, minimizing intraoperative bleeding, and reducing procedure time. Various traction modalities, including snares and grasping forceps, have been applied in previous studies to improve tumor exposure.^21,22 Among these options, dental-floss-assisted external traction offers unique advantages owing to its flexibility, tensile strength, and adjustable length, allowing more precise and stable manipulation during resection.^9,10 Unlike the study by Liu et al., ⁹ we did not emphasize flipping the tumor to maintain the serosal surface oriented toward the endoscope. Instead, our approach focused on improving lesion exposure by actively repositioning the tumor—specifically, by applying traction and grasping to draw the exophytic component from outside the gastric lumen into the lumen. This represents a modified mechanical strategy, shifting from passive exposure to active repositioning of the lesion. By contrast, the study by Zu et al. ¹⁰ combined traction with defect closure techniques to enhance closure efficiency and procedural safety. However, our case primarily addressed the challenge of inadequate exposure during endoscopic resection of GETs. Accordingly, our approach emphasizes optimization of the exposure process rather than the closure strategy.

Furthermore, high-quality randomized controlled trials (RCTs) have demonstrated that dental floss-assisted traction techniques can significantly improve operative field visualization, enhance procedural efficiency, shorten procedure time, and reduce technical difficulty.^23,24 These findings provide a strong evidence-based foundation for the application of floss-assisted traction in endoscopic resection of gastric lesions. However, it should be noted that existing RCTs have primarily focused on intraluminal lesions and endoscopic submucosal dissection settings. For submucosal tumors with predominantly exophytic growth, evidence remains limited, as these lesions are largely located outside the gastrointestinal wall and are often associated with inadequate intraoperative exposure, restricted working space, and poorly defined anatomical planes.

In this context, rather than introducing a novel traction technique, the present case applies an established traction principle to EFTR of exophytic tumors, combined with active repositioning using grasping forceps to draw the extraluminal component into the lumen. This strategy aims to improve lesion exposure and procedural controllability in a technically challenging setting (Supplemental Material).

Conclusions

We successfully performed EFTR for a GET using a dental floss-assisted traction technique combined with tissue forceps, achieving complete resection with an uneventful postoperative course. Our experience suggests that floss-augmented traction can facilitate EFTR by improving exposure and operative stability, thereby offering a feasible and may be safe option for appropriately selected GETs amenable to endoscopic resection. Further studies with larger cohorts are warranted to validate its efficacy and generalizability.

Supplemental Material

sj-docx-1-sco-10.1177_2050313X261448322 – Supplemental material for Dental-floss traction-assisted endoscopic full-thickness resection of a gastrointestinal exophytic tumor: A case report

Supplemental material, sj-docx-1-sco-10.1177_2050313X261448322 for Dental-floss traction-assisted endoscopic full-thickness resection of a gastrointestinal exophytic tumor: A case report by Xingcen Chen, Xiaomei Song, Liwei Shi, Hong Guo and Jin Yu in SAGE Open Medical Case Reports