Gastric Ectopic Pancreas Research Articles

An ensemble machine learning model assists in the diagnosis of gastric ectopic pancreas and gastric stromal tumors

ObjectiveTo develop an ensemble machine learning (eML) model using multiphase computed tomography (MPCT) for distinguishing between gastric ectopic pancreas (GEP) and gastric stromal tumors (GIST) in lesions < 3 cm.MethodsIn this study, we retrospectively collected MPCT images from 138 patients between April 2017 and June 2023 across two centers. Cohort 1 comprised 94 patients divided into a training cohort and an internal validation cohort, while the 44 patients from Cohort 2 constituted the external validation cohort. Deep learning (DL) models were constructed based on the lesion region, and radiomics features were extracted to develop radiomics models, which were later integrated into the fusion model. Model performance was assessed through the analysis of the area under the receiver operating characteristic curve (AUROC). The diagnostic efficacy of the optimal model was compared with that of a radiologist. Additionally, the radiologist with the assistance of the eML model provides a secondary diagnosis, to assess the potential clinical value of the model.ResultsAfter evaluation using an external validation cohort, the radiomics model demonstrated the highest performance in the venous phase, achieving AUROC of 0.87. The DL model showed optimal performance in the non-contrast phase, with AUROC of 0.81. The eML achieved the best performance across all models, with AUROC of 0.90. The use of eML-assisted analysis resulted in a significant improvement in the junior radiologist’s accuracy, rising from 0.77 to 0.93 (p < 0.05). However, the senior radiologist’s accuracy, while improving from 0.86 to 0.95, did not exhibit a statistically significant difference.ConclusioneML model based on MPCT can effectively distinguish between GEPs and GISTs < 3 cm.Critical relevance statementThe multiphase CT-based fusion model, incorporating radiomics and DL technology, proves effective in distinguishing between GEP and gastric stromal tumors, serving as a valuable tool to enhance diagnoses and offering references for clinical decision-making.Key PointsNo studies yet differentiated these tumors via radiomics or DL.Radiomics and DL methodologies unveil potentially distinct phenotypes within lesions.Quantitative analysis on CT for GIST and ectopic pancreas.Ensemble learning aids accurate diagnoses, assisting treatment decisions.Graphical

Gastric Outlet Obstruction Caused by Gastric Ectopic Pancreas With Pseudocyst Formation

Ectopic pancreas refers to presence of pancreatic tissue in locations other than the pancreas (the usual anatomical site). This condition is often asymptomatic but can occasionally cause abdominal pain or other gastrointestinal symptoms. Ectopic pancreatic tissue is mainly observed in the stomach and duodenum and may be accompanied by complications, such as hemorrhage, pancreatitis, gastric outlet obstruction due to pseudocyst, and malignant transformation. We report a rare case of gastric ectopic pancreas accompanied by a pseudocyst that led to gastric outlet obstruction, which improved after endoscopic ultrasonography guided fine-needle aspiration in a young woman with habitual excessive alcohol consumption.

Gastric ectopic pancreas with a pseudocyst.

Ectopic pancreas (EP) is defined as pancreatic tissue that lacks anatomical or vascular connections to the normal pancreas. EP is generally asymptomatic and is detected incidentally during endoscopy. However, due to pseudocyst formation, inflammation, or malignant transformation, it may cause non-specific gastrointestinal symptoms, such as abdominal pain, abdominal discomfort, nausea, vomiting, and bleeding. Pseudocyst formation in EP may result from the retention of exocrine secretions in the absence of connections between the glandular epithelium and gastric lumen. We herein report a case of EP with a pseudocyst associated with epigastric pain. EP with a pseudocyst, although rare, needs to be considered in a differential diagnosis of cystic lesions of the stomach.

Laparoscopic resection and endoscopic submucosal dissection for treating gastric ectopic pancreas.

Gastric ectopic pancreas (GEP) is a rare developmental abnormality that refers to the existence of pancreatic tissue in the stomach with no anatomical relationship with the main pancreas. It is usually difficult to diagnose through histological examination, and the choice of treatment method is crucial. To describe the endoscopic ultrasound characteristics of GEP and evaluate the value of laparoscopic resection (LR) and endoscopic submucosal dissection (ESD). Forty-nine patients with GEP who underwent ESD and LR in the Second Affiliated Hospital of Fujian Medical University from May 2018 to July 2023 were retrospectively included. Data on clinical characteristics, endoscopic ultrasonography (EUS), ESD, and LR were collected and analyzed. The characteristics of EUS and the efficacy of the two treatments were analyzed. The average age of the patients was 43.31 ± 13.50 years, and the average maximum diameter of the lesions was 1.55 ± 0.70 cm. The lesion originated from the mucosa in one patient (2.04%), from the submucosa in 42 patients (85.71%), and from the muscularis propria in 6 patients (12.25%). Twenty-nine patients (59.20%) with GEP showed umbilical depression on endoscopy. The most common initial symptom of GEP was abdominal pain (40.82%). Tumor markers, including carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA-19-9), were generally within the normal range. One patient (2.04%) with GEP had increased CEA and CA-19-9 levels. However, no cancer tissue was found on postoperative pathological examination, and tumor markers returned to normal levels after resecting the lesion. There was no significant difference in surgery duration (72.42 ± 23.84 vs 74.17 ± 12.81 min) or hospital stay (3.70 ± 0.91 vs 3.83 ± 0.75 d) between the two methods. LR was more often used for patients with larger tumors and deeper origins. The amount of bleeding was significantly higher in LR than in ESD (11.28 ± 16.87 vs 16.67 ± 8.76 mL, P < 0.05). Surgery was associated with complete resection of the lesion without any serious complications; there were no cases of recurrence during the follow-up period. GEP has unique characteristics in EUS. LR and ESD seem to be good choices for treating GEP. LR is better for large GEP with a deep origin. However, due to the rarity of GEP, multicenter large-scale studies are needed to describe its characteristics and evaluate the safety of LR and ESD.

Esophageal Atresia and Gastric Ectopic Pancreas: Is There a Real Association?

Heterotopic pancreas (HP) is a condition in which there is well-differentiated pancreatic tissue that lacks any anatomic or vascular contact with the pancreatic gland. It normally arises from the stomach but can be found in other locations. Although it is usually asymptomatic, obstructive symptoms, bleeding, or malignant degeneration can occur. The incidence is very low, but it is significantly more common in patients with esophageal atresia (EA). The aim of this study is to evaluate the incidence of HP in patients with and without EA and to compare the results in both groups. We conducted a 2-year prospective study in pediatric patients who benefited from an upper gastrointestinal endoscopy. Patients were divided into two groups: group "A" comprised patients with EA and group "B" those without EA. The variables analyzed were the clinical presentation, presence of HP, location, associated malformations, genetic disorders, and management. A total of 192 consecutive patients were included in the study: 51 (26.6%) in group A and 141 (73.4%) in group B. Indications for endoscopy in group B were eosinophilic esophagitis in 37 (19.2%) patients, celiac disease in 23 (11.95%) patients, and other disorders in 81 (42.2%) patients. Gastric HP was found in seven patients, all of them in group A. All lesions were hosted in the prepyloric antrum. The prevalence of HP in groups A and B was 13.7 and 0%, respectively (p < 0.05). Female gender was predominant in patients with AE and HP, this result being statistically significant (p = 0.044). No other associated malformation or genetic syndrome studied showed association with HP. Only one patient debuted with upper gastrointestinal (GI) bleeding and required excision, while six patients were asymptomatic. The mean follow-up was 54 months (range: 45-78 months). The incidence of gastric HP is more common in patients with EA, with the female gender being a risk factor for their association. Active search and follow-up is recommended as it may become symptomatic anytime and need resection.

Acinar cell carcinoma of gastric ectopic pancreas origin: a case report and literature review

BackgroundPrimary pancreatic-type acinar cell carcinoma of the stomach is extremely rare, often misdiagnosed, and of unclear origin.Case presentationWe report the case of a primary pure pancreatic-type acinar cell carcinoma of the stomach in a 58-year-old woman. This is the first reported case to exhibit residual ectopic pancreatic tissue adjacent to the tumor serving as evidence for the origin of the carcinoma. Furthermore, we summarized the clinicopathological features of pancreatic-type acinar cell carcinoma of the stomach in order to further understand this solid tumor.ConclusionsPrimary pancreatic-type acinar cell carcinoma of the stomach is rare. Data on tumors of this histological type are still relatively scarce, and more in-depth research is needed to elucidate their molecular biological characteristics and prognosis.

A Multimodal Multipath Artificial Intelligence System for Diagnosing Gastric Protruded Lesions on Endoscopy and Endoscopic Ultrasonography Images.

The aim of this study was to develop a novel artificial intelligence (AI) system that can automatically detect and classify protruded gastric lesions and help address the challenges of diagnostic accuracy and inter-reader variability encountered in routine diagnostic workflow. We analyzed data from 1,366 participants who underwent gastroscopy at Jiangsu Provincial People's Hospital and Yangzhou First People's Hospital between December 2010 and December 2020. These patients were diagnosed with submucosal tumors (SMTs) including gastric stromal tumors (GISTs), gastric leiomyomas (GILs), and gastric ectopic pancreas (GEP). We trained and validated a multimodal, multipath AI system (MMP-AI) using the data set. We assessed the diagnostic performance of the proposed AI system using the area under the receiver-operating characteristic curve (AUC) and compared its performance with that of endoscopists with more than 5 years of experience in endoscopic diagnosis. In the ternary classification task among subtypes of SMTs using modality images, MMP-AI achieved the highest AUCs of 0.896, 0.890, and 0.999 for classifying GIST, GIL, and GEP, respectively. The performance of the model was verified using both external and internal longitudinal data sets. Compared with endoscopists, MMP-AI achieved higher recognition accuracy for SMTs. We developed a system called MMP-AI to identify protruding benign gastric lesions. This system can be used not only for white-light endoscope image recognition but also for endoscopic ultrasonography image analysis.

Gastric Ectopic Pancreas - A Case Report

Ectopic pancreas is a rare embryological abnormality apparently not in association with others. Stomach and duodenum are the most common organs involved. Symptoms are nonspecific.Patients may complain of dyspepsia, abdominal pain or intestinal obstruction. Diagnosis can be very challenging due to the rarity of the disease and the absence of specific symptoms and radiological findings. Here we report a case of Heterotopic pancreas in a gastric tissue in a 23 year old woman admitted to the emergency department due to acute upper gastro-intestinal symptoms.Endoscopic ultrasonography revealed submucosal gastric lesions. The patient underwent abdominal computed tomography, that showed gastric mass originating along the lesser curvature of the stomach. According to the patients symptoms, family history and radiological findings, the patient was scheduled for a surgical resection.In this case, gastric ectopic pancreas was found on routine histopathological examination. Clinical presentation of ectopic pancreas can be challenging, especially in an emergency setting. Diagnostic-therapeutic laproscopy should be considered in symptomatic patients.

Gastric duplication cyst with ectopic pancreas in a teenager successfully resected by endoscopic submucosal dissection

BackgroundGastric duplication cyst associated with ectopic pancreas is rare and we aimed to alert clinician to this congenital anomaly.Case presentationA 15-year-old girl presented with intermittent vomiting. Gastroscopy showed a submucosal tumor with an approximate diameter of 40 mm in the anterior wall of the gastric antrum. The lesion had a central umbilication and was diagnosed preliminarily as gastric ectopic pancreas with pseudocyst formation on the basis of its appearance. However, computed tomographic scan showed a thick-walled cystic lesion with an enhanced outline of the cystic wall in the antrum of stomach, suggestive of duplication cyst. Serum amylase was normal. Endoscopic ultrasonography revealed a solid-cystic lesion; the solid portion were inhomogeneously mixed with echoes, and had indistinct border to muscularis propria; the cystic portion had echogenic internal mucosal layer and distinct border to muscularis propria. Endoscopic submucosal dissection (ESD) was suggested for the patient to relieve symptoms and diagnose the lesion definitely. The operation procedure was uneventful and the solid-cystic lesion was resected completely. Histopathologic examination revealed that the solid portion was ectopic pancreas, and the cystic portion was gastric duplication cyst. After resection, the patient discharged successfully and neither symptoms nor tumors recurred during the 9 months follow-up period.ConclusionsThis is the first case of a solid-cystic lesion with central umbilication in the stomach diagnosed as gastric duplication cyst associated with ectopic pancreas. ESD could be an optional treatment to provide a definitive diagnosis.

S1678 Gastric Ectopic Pancreas With Pseudocyst Formation Causing Gastric Outlet Obstruction

Introduction: Ectopic pancreas (EP) is a rare entity referring to the presence of pancreatic tissue at an anatomic location distinct from the pancreas which is commonly asymptomatic and found incidentally. EP can become symptomatic due to similar pathologic changes found in the anatomic pancreas including pancreatitis, bleeding, or pseudocyst formation. Gastric EP lesions present a diagnostic challenge as they lack distinguishing imaging and endoscopic features from other types of gastric submucosal tumors. This case report describes a rare case of EP presenting as a gastric antral mass with a unique combination of complications: chronic pancreatitis and pseudocyst formation causing gastric outlet obstruction. Case Description/Methods: A 59-year-old man presented to the hospital with nausea, vomiting, weight loss, and epigastric pain for 5 days. Exam was notable for epigastric tenderness, and labs were unremarkable. Computed tomography (CT) and index upper endoscopy showed a 4.4 x 3.5 cm multiloculated cystic mass in the gastric antrum (Figure). Endoscopic ultrasound (EUS) showed that the lesion originated from the submucosa, and fine needle aspiration (FNA) demonstrated histiocytes and epithelial cells with a high amylase level. On repeat endoscopy, interval growth of the cystic gastric mass was observed, and repeat CT abdomen/pelvis again showed the mass now with multiple cystic collections causing mass effect on a distended stomach suggesting gastric outlet obstruction. The lesion was surgically resected and determined to be EP with histologic changes of chronic pancreatitis and multiple pseudocysts. Patient did well after surgical resection and had no recurrence on repeat upper endoscopy. Discussion: EP can occur anywhere in the GI tract but most commonly are found in the duodenum or stomach. Symptoms are associated with the location, size, and pathology of the tissue. Lesions greater than 1.5 cm are more likely to be symptomatic with non-specific symptoms such as epigastric pain, abdominal fullness, nausea, diarrhea or melena. Diagnosis can be challenging, and in this case, multiple diagnostic modalities (imaging, endoscopy, EUS with FNA biopsy and surgical resection) were needed to reach a definitive diagnosis. EP is often found incidentally, and the combination of pseudocyst formation and gastric outlet obstruction in this case has been rarely reported in the literature. Prompt recognition of ectopic pancreas can facilitate the management of these complications.Figure 1.: A: Computed tomography of abdomen and pelvis from initial presentation, showing a multiloculated cystic mass (noted by *) and thickening of the gastric antral wall. B: Esophagogastroduodenoscopy (EGD) image showing a submucosal mass in the gastric antrum. C: Endoscopic ultrasound of gastric antrum with multicystic lesion appearing to originate from the submucosa.

Acute pancreatitis following endoscopic ultrasonography-guided tissue acquisition for gastric ectopic pancreas.

A 37-year-old man was referred to our hospital for further evaluation of the gastric subepithelial lesion accidentally found during screening gastroscopy. The lesion was located on the greater curvature of the gastric body (Fig. 1a). Abdominal computed tomography (CT) demonstrated a 25-mm-diameter homogenously enhanced mass in the gastric wall (Fig. 1b). Endoscopic ultrasonography (EUS) showed a heterogeneous submucosal mass in the 3rd layer of the gastric wall (Fig. 1c). EUS-guided tissue acquisition (EUS-TA) was performed in three passes using a 22-gage Franseen needle (Acquire; Boston Scientific, Marlborough, MA, USA).

Endoscopic submucosal dissection by using a new traction device.

Video 1Patient with a history of gastric ectopic pancreas and epigastric pain. We illustrate the endoscopic submucosal dissection of the ectopic pancreas using a new traction device, the ProdiGi traction wire. Using this device, we were able to resect the lesion en bloc with no adverse events.

A case of ectopic pancreas of the stomach accompanied by intraductal papillary mucinous neoplasm with GNAS mutation

BackgroundEctopic pancreas is basically a benign disease and is not always necessary to be removed. However, all types of neoplasms occurring in the normal pancreas such as ductal adenocarcinomas and intraductal papillary mucinous neoplasms (IPMNs) may develop even within ectopic pancreas. We recently encountered an extremely rare case of ectopic pancreas in the gastric antrum associated with IPMN possessing a GNAS mutation.Case presentationA 71-year-old Japanese woman complained of epigastric pain. Computed tomography and upper gastrointestinal endoscopy showed an intramural cystic mass in the antrum of the stomach. Endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) biopsy did not give a definitive diagnosis, and the patient underwent resection of the lesion. Histology of the resected specimen showed that the gastric intramural lesion was ectopic pancreas. Moreover, the lesion contained dilated duct components with tubulo-villous epithelial proliferation consistent with pancreatic IPMN. Since the covering epithelial cells had highly atypical nuclei, the lesion was diagnosed as IPMN with high grade dysplasia. Immunohistochemistry showed that the IPMN component showed to be MUC2-, MUC5AC-, and CDX2-positive but MUC1- and MUC6-negative. Mutational analyses using genomic DNA revealed that the IPMN component had a mutation of GNAS at exon 8 (Arg201Cys).ConclusionWe finally diagnosed this case as gastric ectopic pancreas accompanied by intestinal type IPMN with high grade dysplasia possessing GNAS mutation. Although there were 17 cases of ectopic pancreas with IPMN including 6 cases of gastric ones reported in the English literature, this is the first case of ectopic pancreas with IPMN which was proved to have GNAS mutation. Intimate preoperative examinations including imaging analyses and EUS-FNA biopsy/cytology are recommended to decide whether the lesion has to be resected or not even if they are not effective for getting the right diagnosis.

CT differentiation of gastric ectopic pancreas from gastric stromal tumor

BackgroundGastric ectopic pancreas (GEPs) is a rare developmental anomaly which is difficult to differentiate it from submucosal tumor such as gastric stromal tumor (GST) by imaging methods. Since the treatments of the GEPs and GST are totally different, a correct diagnosis is essential. Therefore, we retrospectively investigated the CT features of them to help us deepen the understanding of GEPs and GST.MethodsThis study enrolled 17 GEPs and 119 GST, which were proven pathologically. We assessed clinical and CT features to identify significant differential features of GEPs from GST using univariate and multivariate analyses.ResultsIn univariate analysis, among all clinicoradiologic features, features of age, symptom, tumor marker, location, contour, peritumoral infiltration or fat-line of peritumor, necrosis, calcification, CT attenuation value of unenhancement phase/arterial phase/portal venous phase (CTu/CTa/CTp), the CT attenuation value of arterial phase/portal venous phase minus that of unenhanced phase (DEAP/DEPP), long diameter (LD), short diameter (SD) were considered statistically significant for the differentiation of them. And the multivariate analysis revealed that location, peritumoral infiltration or fat-line of peritumor, necrosis and DEPP were independent factors affecting the identification of them. In addition, ROC analysis showed that the test efficiency of CTp was perfect (AUC = 0.900).ConclusionLocation, the presence of peritumoral infiltration or fat-line of peritumor, necrosis and DEPP are useful CT differentiators of GEPs from GST. In addition, the test efficiency of CTp in differentiating them was perfect (AUC = 0.900).

Management of gastrointestinal subepithelial tumors with endoscopic resection

AbstractThe diagnosis and management of gastrointestinal subepithelial tumors (GI SETs) have been under debate because of the low biopsy yield rate and risk of surgery. Owing to the advancement in endoscopic submucosal dissection (ESD) and submucosal tunneling endoscopic resection (STER), GI SETs may be resected under acceptable risk, and the nature of GI SETs can be studied. However, the efficacy of endoscopic resection in the diagnosis and management of GI SETs remains unclear. We present our single‐hospital experience of resecting GI SETs with ESD and STER to explore the efficacy of this technique and the nature of GI SETs. Thirty‐nine patients with GI SETs who underwent ESD and STER were analyzed retrospectively. Patients' clinical data, procedure parameters, pathologic diagnosis, and outcomes were collected and analyzed. Thirty‐nine GI SETs were resected, 36 by ESD, and 3 by STER. Thirty‐eight (97.4%) tumors were from the submucosal layer and one from the muscular layer. Fifteen, 13, and 11 tumors were located in the esophagus, stomach, and colon, respectively. The mean tumor size was 16.8 ± 1.3 mm. In the esophagus, leiomyomas were the most common diagnosis, followed by the lymphoepithelial cyst, epithelial hyperplasia, focal lymphoid hyperplasia, and dilated submucosal gland. The esophageal tumor from the muscularis propria was GI stromal tumor (GIST). In the stomach, 53.8% of the submucosal tumors were ectopic pancreas, followed by lipoma, calcifying fibrous tumor, GIST, submucosal inflammation, and angiodysplasia with focal ulcers. The submucosal tumors in the colon were diagnosed as neuroendocrine tumors (NETs, n = 5), lipomas (n = 4), leiomyoma (n = 1), and foreign body‐related granuloma (n = 1). Seven (17.9%) of all tumors were NETs and GISTs with malignant potential. All cases were resected completely. The overall procedural time was 37.9 ± 4.6 minutes. Severe fibrosis was more likely encountered in the stomach with a rate of 46.1%, with the gastric ectopic pancreas having a 71.4% severe fibrosis rate. Only 13 patients completed follow‐up endoscopic ultrasound or endoscopy within 1 year after ESD and STER, and no recurrence was noted. There were no major complications, and none of the patients required admission to the intensive care unit or surgery. Three perforations were encountered during STER, which were smoothly managed with hemoclips without surgery. ESD and STER can be an effective modality for the diagnosis and management of GI SETs in a selected group of patients. Most of the lesions are benign, whereas some have malignant potential. More studies on the nature of GI SETs are required to justify the indications of endoscopic resection.

Endoscopic and Endosonographic Features of Histologically Proven Gastric Ectopic Pancreas by Endoscopic Resection.

Distinguishing gastric ectopic pancreas (GEP) from malignant tumors is relatively difficult. This study evaluated the endosonography findings of pathologically proven GEP. Thirty-one patients diagnosed with GEP based on a histopathological analysis from January 2004 to July 2018 were enrolled in this study. All patients underwent EUS and an endoscopic resection. Seventeen patients were female, and the median age was 41.1 years (range, 14-74). The lesions were localized most commonly in the antrum. The mean size of the GEP was 10.6 mm (range, 7-15). Superficial type lesions, lesions with heterogeneous echogenicity, mixed pattern lesions, and lesions with indistinct borders were commonly observed on EUS. Calcification, anechoic duct-like structures, and thickening of the muscularis propria were observed in some patients. Endoscopic mucosal resection (41.9%) and endoscopic submucosal dissection (58.1%) were performed. The mean procedure time was 22.5 minutes. Complete resection was achieved for 71% of patients. No statistically significant results between the endosonography findings and complete resection rates were obtained. The mean follow-up esophagogastroduodenoscopy duration was 4.5 months. None of the patients presented with residual lesions on subsequent endoscopy. EUS can help identify the features of GEP. Careful observations of the EUS findings can avoid unnecessary removal of GEP.

Ectopic pancreas mimicking gastric submucosal tumour treated using robotic surgery.

Gastric ectopic pancreas presenting as a submucosal tumour accounts for approximately 11% of all endoscopic ultrasonography (EUS) examinations. Definitive diagnosis through endoscopy is difficult, even with EUS-guided fine-needle aspiration biopsy for histological examination. For symptomatic patients or those with uncertain diagnosis, complete surgical resection is the primary strategy for treatment and diagnosis. Herein, we report a case of gastric ectopic pancreas treated using robotic surgery.

A Case of Gastric Ectopic Pancreas in Two Locations Presenting with Epigastralgia

症例は23歳の女性で，心窩部痛を主訴に当院紹介となる．上部消化管内視鏡検査で胃角後壁に約25mm大の隆起性病変を認め，腹部造影CTで胃体下部大彎側に約35mm大，胃角部後壁に約16mm大の造影効果が膵と類似した病変を認めた．胃粘膜下腫瘍としてgastrointestinal stromal tumor （以下，GISTと略記）や平滑筋腫，異所性膵などが鑑別として考えられたが，GISTが否定しきれないことから手術の方針となった．術中の肉眼的所見はどちらも膵組織であり，異所性膵と診断した．二つの病巣に対して2箇所で胃部分切除術を施行し摘出した．術後に心窩部痛は消失した．術後病理学的組織診断は，ともに異所性膵であり，それぞれ胃壁の固有筋層から漿膜下層および粘膜下層から固有筋層に存在していた．一部の膵管周囲に組織球の小集簇を伴う線維化巣も認められたため，心窩部痛に際して限局的膵炎を発症していた可能性が疑われた．臨床症状を伴い，2箇所に存在する異所性膵はまれであり，報告した．

1306 Endoscopic Mucosal Resection of Pancreatic Rest Presenting as a Submucosal Nodule in the Gastric Antrum

INTRODUCTION: Pancreatic rest (PR) is defined as ectopic pancreatic tissue outside the normal pancreatic parenchyma, with a vascular and nerve supply separate from the pancreas itself and has a prevalence of 0.55-14%. It is believed to arise during rotation of the foregut, when fragments of the pancreas become separated from the main body and are deposited at ectopic sites. CASE DESCRIPTION/METHODS: An 82-year-old male with a history of GERD presented with episodes of epigastric abdominal pain of 2 month duration that did not improve despite PPI therapy. He denied any other symptoms such as bleeding, weight loss or change in bowel habits. Physical examination revealed a non-distended abdomen and mid-epigastric tenderness. An EGD performed for evaluation of GERD 3 years prior found an antral nodule. A repeat EGD was done this time for evaluation of the epigastric pain and showed a mobile submucosal nodule in the antrum measuring 7-8 mm, unchanged from before. EUS was performed for further evaluation and showed a hypoechoic gastric submucosal lesion, arising from the muscularis mucosa, 8 mm in size. No high-risk features were present. The area was resected using EMR and the defect was closed with clips. The EUS also showed a cystic dilation of the pancreatic duct in the pancreatic head measuring 5 mm, suspicious for main duct IPMN. Results from the EMR biopsy demonstrated heterotopic pancreatic tissue with focal low grade pancreatic intraepithelial neoplasia (PanIN), with clear margins and reactive gastropathy with focal intestinal metaplasia. There was resolution of the abdominal pain after the procedure. A repeat EGD/EUS will be done in 1 year. MRI will be performed in 6 months for surveillance of the pancreatic duct dilation. DISCUSSION: PR can be found virtually anywhere along the GI tract, but they are typically found in the stomach along the greater curvature and antrum. Although usually asymptomatic, the most reported symptom is mid abdominal pain. Complications of gastric ectopic pancreas include acute or chronic pancreatitis, necrosis, pseudocyst, gastric outlet obstruction and rarely carcinoma. PanIN is neoplastic epithelial proliferation that occurs in the small caliber pancreatic ducts; it is divided in 3 degrees based on architectural and nuclear atypia and has potential progression to invasive ductal adenocarcinoma. In our case, PanIN 1 was found on histology and the lesion was completely resected. PR should always be considered when evaluating a submucosal lesion of the GI tract.

Endoscopic Resection of Gastric Submucosal Masses by a Dental Floss Traction Method.

Background and Aims ESE (endoscopic submucosal excavation) is widely used for the treatment of digestive diseases. The dental floss traction (DFT) method has been successfully used to facilitate ESE to resect mucosal lesions such as early gastric cancer. DFT has not been used in ESE to remove submucosal masses. This study aimed to examine the efficacy of DFT-assisted ESE (DFT- ESE) for the removal of submucous masses. Methods From March 2017 to May 2017, a total of 12 patients with gastric submucosal masses at the First Affiliated Hospital of Nanchang University, Jiangxi, China, were enrolled. The tumor characteristics, en bloc resection rates, complications, and outcomes on follow-up were evaluated for all patients. Results The 12 submucosal tumors were completely removed by DFT- ESE. Nine were gastrointestinal stromal tumors. Two were Schwannoma, located in the greater curvature of the gastric corpus. One was gastric ectopic pancreas. All the resected tumors were removed completely with intact tumor capsules. There was no more bleeding or perforation after the endoscopic closure of the perforation or the wound after the DFT-ESE, and no recurrences were identified at the time of follow-up. Conclusions The DFT method efficiently and safely facilitated the ESE procedure during the resection of gastric submucosal tumors. This study was registered with Chinese Clinical Trial Registry under Registration number ChiCTR-OOC-15005833).