Endoscopic submucosal dissection (ESD) is an effective treatment for the complete resection of early gastric cancer and precancerous lesions. Compared to endoscopic mucosal resection, ESD has the advantage of enabling en bloc resection of larger lesions [1]. However, various complications such as bleeding, perforation, and stricture can occur after ESD, and it has been reported that the risk of stricture increases when extensive lesions are resected in the antrum [2].

Stricture after ESD can lead to gastric outlet obstruction (GOO) due to fibrosis and scar formation in the submucosal layer. This can cause difficulties in food passage, negatively impacting the patient’s nutritional status and quality of life. The primary treatment for antral stricture is endoscopic balloon dilation (EBD) [3], and in some cases, endoscopic antralplasty can be performed [4]. Meanwhile, local steroid injection therapy can be used to inhibit the fibrotic response in the submucosal layer, preventing stricture formation. Steroids play a role in preventing excessive fibrosis during the wound healing process through their anti-inflammatory and antifibrotic effects [5]. However, if deformity-induced stricture is severe and continues to recur despite the aforementioned procedures, additional treatment strategies are required.

Although rarely performed, another treatment option is the placement of a self-expandable metal stent (SEMS). This method has relatively fewer severe complications aside from stent migration and offers the advantage of maintaining prolonged expansion of the stricture site without the need for repeated procedures. Thus, it can be considered a non-surgical treatment option for benign pyloric stenosis [6,7].

The authors report a case of antral stricture with GOO that developed after ESD for a large adenoma in the antrum. Despite repeated endoscopic antralplasty, the patient continued to experience bleeding and GOO. Consequently, SEMS placement was performed, successfully resolving the condition.

A 79-year-old male patient visited the hospital for the removal of a low-grade adenoma detected during a routine health check-up. The patient was not on any antiplatelet or anticoagulant therapy. Fifteen years ago, he had undergone ESD for an adenoma at the gastric angle, followed by argon plasma coagulation (APC) ablation due to lateral margin involvement. Endoscopy revealed a large adenoma approximately 5 cm in size, involving the angle, antrum anterior wall side, and lesser curvature side, while the pyloric ring remained intact (Fig. 1). ESD was performed successfully, and in the angle region, where severe mucosal adhesion was observed due to previous ESD and APC ablation, partial resection of the muscle layer was necessary to achieve complete removal (Fig. 2). The procedure was completed without complications, and the patient was discharged on the second day post-procedure with a hemoglobin level of 14.2 g/dL. Acid suppression therapy with a potassiumcompetitive acid blocker (P-CAB, tegoprazan 50 mg) was initiated immediately after ESD.

Two weeks post-discharge, the patient returned with symptoms of dyspepsia and melena. He experienced appetite loss and a weight reduction of approximately 5 kg due to persistent bloating and discomfort. Laboratory tests showed a hemoglobin level of 11.2 g/dL. Endoscopic evaluation revealed food retention, spontaneous blood oozing at the ESD site, and difficulty passing the scope through the pyloric ring. The ulcer stricture at the ESD site resulted in antral deformity and GOO, hindering proper healing due to prolonged food retention and continuous exposure to gastric acid (Fig. 3). Given the extensive nature of the stricture, EBD was deemed ineffective, and endoscopic incision antralplasty was planned.

Submucosal injection was performed on the greater curvature side of the antrum, opposite the ESD ulcer, followed by longitudinal incision using a knife. The incision widened the antral space, facilitating easier visualization and passage through the pyloric ring (Fig. 4A). To prevent re-stricture, multiple submucosal steroid (triamcinolone 10 mg) injections were administered at the incision site. Follow-up endoscopy performed 4 days later showed no food retention or bleeding, and the antrum remained adequately dilated (Fig. 4B).

At 2 weeks post-procedure, follow-up endoscopy revealed recurrent GOO due to re-stricture at the incision site. Additional longitudinal incisions and steroid injections were performed on the surrounding intact mucosa. Despite these interventions, the patient presented again with recurrent symptoms and bleeding. Endoscopic examination confirmed persistent GOO due to recurrent stricture (Fig. 5A). Given the ineffectiveness of further incision procedures, SEMS placement was chosen as the next treatment strategy.

A partially covered SEMS (Niti-S^TM ComVI pyloric/duodenal stent Flare-Skirt type, 24×100 mm; TaeWoong medical Co.,Ltd.) was placed across the antrum and duodenum, centered at the pyloric ring, 10 weeks after the initial ESD (prior two sessions of endoscopic antralplasty were performed at weeks 6 and 8, respectively). A custom made wide-diameter SEMS with anti-migration properties (diameter of proximal end 38 mm) was selected to prevent migration. The covered portion was positioned at the ulcer stricture site to aid in both mechanical dilation and bleeding control, while the uncovered 15 mm wide portion was placed towards the lower body to facilitate future removal (Fig. 5B). The patient’s symptoms improved post-SEMS placement, and no further bleeding was observed. Closed X-ray follow-ups were conducted to monitor potential SEMS migration, and the SEMS was removed 4 weeks later (Fig. 5C). P-CAB was maintained continuously throughout the clinical course. The patient subsequently remained symptom-free, tolerated an oral diet well, regained weight, and maintained stable hemoglobin levels.

Antral stricture after ESD is particularly challenging to treat due to the anatomical characteristics of the stomach, and if the stricture persists, it can lead to GOO, significantly impacting the patient’s nutritional intake [8]. Major risk factors for stricture formation include the extent of mucosal resection, the degree of submucosal layer damage, and the presence of bleeding or infection [3,9]. Reports indicate that strictures often occur when lesions occupy more than two-fifths of the antrum and typically develop within 6 weeks post-procedure [10].

EBD has been the most widely performed treatment for antral or pyloric strictures after ESD. However, in benign pyloric strictures, the success rate of EBD remains suboptimal, with persistent symptom resolution reported in 16%–70%, emergency surgery due to perforation in 2.8%–4.3%, and repeated procedures required in 22%–32% of cases [11,12]. In some patients, endoscopic antralplasty via incision may be effective [4,13,14]. Endoscopic antralplasty involves creating another ulcer by endoscopically incising the mucosa opposite the ESD ulcer, allowing traction forces to expand the gastric lumen. Predicting the direction of traction is difficult, and in severe cases of antral deformity, as seen in this case, repeated procedures may not sufficiently prevent recurrence of the stricture. Local steroid injection is sometimes performed after the incision to prevent re-stricture; however, steroid use carries a risk of delayed perforation or infection [15]. We did consider the use of oral steroids or intralesional steroid injections or both to prevent stricture formation in this case. However, we ultimately decided not to administer steroids. Although several studies have reported the effectiveness of oral steroid therapy in preventing strictures after esophageal ESD [16,17], particularly in cases involving circumferential or near-circumferential resections, the evidence supporting its use in gastric or antral lesions is still limited and inconclusive [18].

If mucosal treatments such as EBD or endoscopic antralplasty prove ineffective, the placement of partially covered SEMS can be an effective treatment option [19]. SEMS were originally developed for the treatment of malignant obstructions of the esophagus, colon, and gastric outlet, demonstrating comparable outcomes to surgery in terms of symptom relief and preoperative bridging therapy [20]. However, there are limited reports on the effectiveness of SEMS in benign pyloric obstruction. A study of 11 patients with benign gastrointestinal strictures reported a 27% migration rate following SEMS placement for 3 weeks, with a 36% recurrence rate over 13 months, suggesting that SEMS is a safe and effective treatment [21].

One of the major challenges of SEMS placement is SEMS migration, particularly in benign pyloric strictures where stent removal is necessary. Covered SEMS are preferred in such cases. To mitigate migration, anchoring techniques or longer SEMS may be used, with partially covered SEMS demonstrating lower migration rates than fully covered SEMS. SEMS placement has been reported to be more effective in treating primary benign pyloric strictures without prior EBD [19]. Another advantage of covered SEMS is their ability to control bleeding while maintaining lumen patency, allowing for mucosal healing. In this case, a 24 mm custom made SEMS was used instead of a conventional pyloric SEMS (diameter 20 mm) to completely cover the ulcerated area, providing compression to control oozing and reducing exposure to gastric acid to promote heal-ing. Additionally, a flare-type SEMS with a proximal end diameter of 38 mm was selected to minimize migration risk.

Determining the optimal SEMS duration is crucial. Currently, there are no clear guidelines on the ideal duration of covered SEMS placement in benign pyloric stenosis. Prolonged placement of partially covered SEMS may result in mucosal overgrowth or epithelial ingrowth, making removal difficult and increasing the risk of perforation or bleeding. Conversely, early removal may reduce complications but may also increase the likelihood of recurrence if tissue regeneration is insufficient. Previous studies have shown that SEMS can be safely removed within 8 weeks, suggesting that removal within this period is feasible [22]. Some studies have set an 8-week placement duration based on the estimated healing time for iatrogenic ulcers caused by ESD [7]. Choi et al. [6] reported that among 22 patients who received SEMS for benign pyloric stricture, 7 (31.8%) underwent endoscopic removal after 6–8 weeks, whereas 15 (68.2%) experienced migration (8 cases within 2 weeks and 7 cases between 3–8 weeks). This suggests that a placement period of 6–8 weeks may be optimal, though further research is needed to address migration issues. In contrast, Heo and Jung [19] reported longer placement durations of 3–6 months, with only one case of irretrievable SEMS, indicating that prolonged placement may be feasible. In this case, a 24 mm diameter SEMS with flare type was used to reduce the risk of migration, and the SEMS was removed after 4 weeks to minimize complications. No recurrence of stricture was observed after removal.

This case report presents a case of post-ESD stricture following resection of a large antral adenoma. Despite performing endoscopic antralplasty, persistent stricture and bleeding necessitated the placement of a partially covered SEMS for 4 weeks, leading to successful resolution. When conventional endoscopic dilation and antralplasty fail, partially covered SEMS may serve as an effective treatment option, particularly in cases of recurrent stricture or concurrent bleeding. Future studies should further analyze the optimal SEMS placement duration and removal timing, as well as explore adjunctive therapies to prevent stricture recurrence. Additionally, largescale studies are needed to evaluate long-term outcomes and identify strategies to minimize SEMS-related complications.