Early Gastric Cancer Detected During 15‐year Surveillance After Ménétrier Disease Remission and Successfully Treated With Endoscopic Submucosal Dissection: A Case Report

Apparent Endoscopic Decrease in the Size of a Large Ulcerated Gastric Schwannoma After Helicobacter pylori Eradication Therapy: A Case Report

ABSTRACT Gastric subepithelial lesions (SELs) comprise a heterogeneous group of tumors, among which gastric schwannomas are rare and generally benign. We report a case of a large gastric schwannoma with ulceration and symptomatic anemia that showed an apparent endoscopic decrease in size following Helicobacter pylori eradication. An 85‐year‐old man presented with iron deficiency anemia. Esophagogastroduodenoscopy revealed a large ulcerated SEL in the lower body of the stomach, along with multiple gastric ulcers. Endoscopic ultrasonography demonstrated a 56 mm tumor originating from the fourth layer, raising suspicion for a gastrointestinal stromal tumor. Boring biopsy from the ulcer base enabled a definitive diagnosis of gastric schwannoma based on immunohistochemical findings. Although surgical resection was recommended, the patient declined. After successful H. pylori eradication, follow‐up endoscopy at 6 months showed healing of the ulcerative lesion and an apparent endoscopic decrease in the size of the tumor. Although objective post‐treatment assessment was unavailable, this case suggests that inflammatory or ulcer‐related changes associated with H. pylori infection may influence the endoscopic appearance of gastric SELs.

Gastric Metastasis of Uterine Leiomyosarcoma Detected During Surveillance Endoscopy and Resected by Endoscopic Submucosal Dissection After Multiple Metachronous Metastases: A Case Report

ABSTRACT Uterine leiomyosarcoma (uLMS) is a rare, aggressive uterine malignancy that usually metastasizes hematogenously, whereas gastrointestinal involvement is uncommon. A 69‐year‐old woman with uLMS treated by hysterectomy and adjuvant chemotherapy developed metachronous lung, sigmoid colon, gallbladder, and abdominal wall metastases. After treatment of these metastases, periodical surveillance endoscopy revealed a 15‐mm subepithelial lesion with a shallow central depression in the lower gastric body. Endoscopic ultrasonography showed a well‐defined submucosal lesion without muscularis propria invasion, and biopsy confirmed metastatic leiomyosarcoma. Endoscopic submucosal dissection (ESD) was performed, achieving en bloc resection without adverse events. This rare metachronous combination of gastric, colonic, and gallbladder metastases highlights that incidental gastric metastasis may occur during prolonged disease courses and suggests that ESD may be a useful minimally invasive option for local control of small gastric metastases.

P1.151. Management of Antral Adenocarcinoma 14 Years After Esophagectomy With Gastric Pull-Up: A Surgical Challenge

Esophageal Cancer: Other An 84-year-old male had previously undergone a three-field esophagectomy with gastric pull-up reconstruction for stage I adenocarcinoma of the distal esophagus 14 years earlier. He remained disease-free during long-term follow-up. He subsequently presented with progressive dysphagia and mild, unintentional weight loss. Upper gastrointestinal endoscopy and endoscopic ultrasound demonstrated a stage II adenocarcinoma of the gastric antrum arising within the gastric conduit. Positron emission tomography–computed tomography demonstrated no evidence of metastatic disease. Comprehensive geriatric assessment was performed and confirmed that the patient was functionally independent, with preserved physiological reserve and no major contraindications to oncologic treatment or surgical intervention. His case was discussed at a multidisciplinary team meeting. The patient’s goals of care and treatment preferences were carefully explored, and upfront surgical management with curative intent was recommended. Several surgical strategies were considered. These included total gastrectomy of the gastric conduit with reconstruction using colon transposition or small-bowel supercharged reconstruction, as well as a more limited resection in the form of antrectomy. While total gastrectomy would have ensured maximal oncologic clearance, it may be associated with significant operative complexity and potential morbidity, particularly in the context of advanced age and prior extensive upper gastrointestinal surgery. After careful consideration of oncologic feasibility, technical factors, and patient-specific risk, a limited antrectomy with preservation of the right gastroepiploic artery was selected in order to maintain conduit vascularity and minimize surgical trauma. Surgery was performed successfully, with meticulous preservation of the right gastroepiploic artery supplying the gastric conduit. Adequate oncologic resection margins were achieved. The postoperative course was uneventful, with no surgical or medical complications, and the patient recovered well. Learning point: Secondary gastric malignancy within a gastric pull-up conduit is a rare but clinically significant late complication following esophagectomy. Management requires individualized decision-making, balancing oncologic principles with patient factors and complex reconstructive considerations. In selected patients, limited resection with preservation of conduit blood supply can provide a safe and effective surgical option, emphasizing the importance of multidisciplinary evaluation and tailored surgical strategy.

Liquid Biopsy for Molecular Residual Disease Detection and Postoperative Surveillance in Gastric Cancer: Current Evidence and Future Directions

Gastric cancer remains a major cause of cancer mortality worldwide, mainly due to its frequent diagnosis at advanced stages and the high probability of recurrence even after curative treatment. Conventional postoperative follow-up is mainly based on imaging studies, endoscopy and serological tumor markers, such as carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), and carbohydrate antigen 72-4 (CA72-4)This narrative review was based on a structured literature search of PubMed, Scopus, Web of Science, MEDLINE, the Cochrane Library, and ClinicalTrials.gov from database inception through June 2026, with 75 studies included in the final narrative synthesis. Among these analytes, circulating tumor DNA (ctDNA)currently provides the most mature data for the detection of molecular residual disease and postoperative risk stratification. Although it allows for the early detection of recurrent or residual disease prior to imaging confirmation, postoperative ctDNA has shown significant prognostic value in many studies; however, routine use as a basis for decision-making in treatment planning is still considered investigational and will require future prospective clinical validation. Tumor-informed ctDNA approaches offer high analytical specificity and sensitivity in low-burden disease settings. In contrast, tumor-agnostic approaches, such as methylation analysis and fragmentomics, may improve the scalability of the method. However, they require further validation in the postoperative setting. At the same time, emerging data indicate that extracellular vesicles, exosomal RNA and peritoneal lavage analytes can provide complementary biological information, especially in cases of peritoneal dissemination. Despite the significant prospects, the use of liquid biopsy in guiding the treatment of gastric cancer remains under investigation. This is because even today there are limitations. Characteristic are the low ctDNA excretion and the anatomical heterogeneity of the disease, as well as clonal hematopoiesis. Limitations also include the lack of standardization as well as the cost and the need for prospective clinical studies. This review summarizes the biological basis of molecular residual disease, liquid biopsy technologies, ctDNA data, the concept of molecular recurrence, and the future prospects of multi-analytic and artificial intelligence (AI)-assisted surveillance models in gastric cancer.

Pathological Complete Response in a Patient With HER2-Negative Esophagogastric Junction Cancer Undergoing Conversion-Intent Surgery After Ramucirumab Plus Paclitaxel Following Nivolumab-Based Chemotherapy: A Case Report

CA19-9-producing esophagogastric junction cancer with nodal recurrence outside the planned dissection field: a case report

The biological behavior of CA19-9-producing esophagogastric junction cancer (EGJC) remains poorly understood, although some reports suggest that CA19-9 expression reflects a more aggressive subtype. We report a 64-year-old man with Siewert type II EGJC, presenting with 3.5 cm of esophageal invasion and markedly elevated serum CA19-9 levels (11 630 U/mL). Following neoadjuvant chemoradiotherapy, thoracoscopic Ivor Lewis esophagectomy with lower mediastinal lymphadenectomy was performed. Histopathology confirmed a CA19-9-producing adenocarcinoma. Twenty months postoperatively, a solitary recurrence in the No.109 L mediastinal lymph node, outside the planned dissection field, was identified. Salvage lymphadenectomy via left thoracotomy achieved R0 resection. Adjuvant chemoradiotherapy was subsequently administered. The patient remains recurrence-free 38 months after the salvage surgery. This case demonstrated nodal recurrence outside the planned dissection field despite limited esophageal invasion. The findings suggest that biological tumor characteristics, including elevated CA19-9 expression, may contribute to recurrence patterns not fully predicted by current lymphadenectomy algorithms. Moreover, timely salvage surgery in cases of solitary nodal recurrence can result in favorable long-term outcomes. In conclusion, CA19-9-producing EGJC may exhibit biologically aggressive features. This case suggests that elevated CA19-9 expression may represent a factor associated with recurrence beyond the planned dissection field. Further studies are needed to clarify whether tumor biology should be incorporated into surgical decision-making in EGJC.