A Case of Duodenal Adenocarcinoma Effectively Highlighted by Linked Color Imaging and Confirmed by Histopathology.

While the differential diagnosis of duodenal adenocarcinoma versus adenoma remains the key to determining treatment strategies in patients with suspected duodenal adenocarcinoma, the role of linked color imaging (LCI) in their differential diagnosis remains insufficiently documented. In this case, esophagogastroduodenoscopy (EGD) was performed on a 67-year-old man for anemia, which revealed a 20-mm-sized, whitish, partially reddish, pedunculated lesion located in the duodenal bulb on white light imaging. Using LCI, the lesion was highlighted as a whitish, pedunculated lesion with its central and inferior areas depicted as orangish and reddish, respectively. Endoscopic mucosal resection was performed on the suspicion of an adenocarcinoma for biopsy and endoscopic diagnosis. Histological examination revealed the lesion to be an adenocarcinoma contained in an adenoma: papillary, type 0-Ip, measuring 20x20 mm, pTis (M), involving no lymphovascular invasion. This case appears to underpin the usefulness of LCI in the differential diagnosis of duodenal adenocarcinoma.

Familial Adenomatous Polyposis with Atypical Clinical Morphology and Genetic Variants.

Familial adenomatous polyposis (FAP) is caused by pathogenic variants of the APC gene on the long arm of chromosome 5. An analysis showed an association between germline APC gene variants and clinical signs of FAP; however, attenuated FAP has also been reported in cases with pathogenic variants. In contrast, a phenotype of FAP with no APC germline pathogenic variant and with few signs has been reported. We herein report a 16-year-old girl in whom the presence of multiple large bowel cancers from a young age and several small bowel cancers reflected a carcinogenic tendency higher than that typical for FAP.

Progression of duodenal neoplasia to advanced adenoma in patients with familial adenomatous polyposis.

BACKGROUND: Patients with familial adenomatous polyposis (FAP) have a lifetime risk of developing duodenal adenomas approaching 100%, and the relative risk for duodenal cancer compared with the general population is high. We conducted a retrospective study to investigate the progression of non-ampullary duodenal adenomas (NADAs) and risk factors for advanced lesions in patients with FAP. METHODS: Of 248 patients with 139 pedigrees at 2 institutes, we assessed 151 patients with 100 pedigrees with a pathogenic germline variant in the adenomatous polyposis coli gene, excluding mosaic variants. We evaluated the prevalence of NADAs in patients with FAP, the progression of these adenomas to advanced adenoma during the observation period, and the risk factors for the lifetime development of high-grade dysplasia (HGD), large (≥ 10 mm) duodenal adenomas, and Spiegelman stage IV. RESULTS: During the median observation period of 7 years, the incidences of patients with NADAs, with more than 20 polyps, with polyps ≥ 10 mm, with HGD, and with stage IV at the last esophagogastroduodenoscopy were increased 1.6-fold, 1.7-fold, 5-fold, 22-fold, and 9-fold, respectively. Intramucosal cancer occurred in three patients (2%), but no patients developed invasive cancer during the observation period because we performed endoscopic intervention for advanced adenomas. Stage progression was observed in 71% of 113 patients. Stage IV was more common in women, patients with a history of colectomy, and those with a 3' side mutation in their adenomatous polyposis coli gene. CONCLUSIONS: NADAs in patients with FAP frequently become exacerbated. Our findings suggest that patients with FAP who develop duodenal adenomas should be surveyed to prevent the development of duodenal cancer.

Transmesenteric approach for laparoscopic endoscopic cooperative surgery for a duodenal adenoma located in the third portion of the duodenum.

We report our experience in a patient with adenoma located in the horizontal part of the duodenum, which was effectively treated with the transmesenteric laparoscopic endoscopic cooperative surgery (LECS) approach. This approach, which entails incising the mesentery of the colon, simplified laparoscopic access to the horizontal part of the duodenum, which was minimally mobilized. Thus, the bulb and descending part of the duodenum were fixed to the retroperitoneum, facilitating stable handling of the endoscope and enabled safe and effective excision of an adenoma located in the horizontal part of the duodenum. This approach enabled safe and effective excision of an adenoma located in the horizontal part of the duodenum. The advantages of this method include a secure field of view, lower probability of damage to large vessels, and minimizing the defect to the intestine caused by the incision.

Clinical outcomes: endoscopic resection of duodenal ampullary lesions.

Background: Ampullary adenomas are lesions at the duodenum's major papilla commonly associated with familial adenomatous polyposis (FAP) but may also occur sporadically. Historically, ampullary adenomas were removed surgically, however endoscopic resection has become the preferred method of resection. Most of the literature on management of ampullary adenomas are small single-center retrospective reviews. The objective of this study is to describe endoscopic papillectomy outcomes to further refine management guidelines. Methods: This is a retrospective study of patients who underwent endoscopic papillectomy. Demographic data were included. Details regarding lesions and procedures were also collected, including endoscopic impression, size, resection method and adjunctive therapies. Chi-square, Kruskal-Wallis rank-sum, and t-tests were performed. Results: A total of 90 patients were included. 60% patients (54 of 90) had pathology-proven adenomas. 14.4% of all lesions (13 of 90) and 18.5% of adenomas (10 of 54) were treated with APC. Among APC-treated lesions, 36.4% developed recurrence (4 of 11) vs. 7.1% developed residual lesion (1 of 14) (P=0.019). 15.6% of all lesions (14 of 90) and 18.5% of adenomas (10 of 54) reported complications, and the most common was pancreatitis (11.1% and 5.6%). Median follow-up time was 8 months for all lesions and 14 months (range, 1-177 months) for adenomas, with time to recurrence 30 and 31 months (range, 1-137 months), respectively. Recurrence was observed in 16.7% of all lesions (15 of 90) and 20.4% of adenomas (11 of 54). Endoscopic success was observed in 69.2% of all lesions (54 of 78) and 71.4% of adenomas (35 of 49) after removing patients lost to follow-up. Conclusions: Endoscopic papillectomy is an effective method for managing duodenal adenomas. Pathology-proven adenoma should undergo surveillance for at least 31 months. Lesions treated with APC may require closer follow-up and for a prolonged period.

Endoscopic therapy of sporadic non-ampullary duodenal adenomas, single centre retrospective analysis.

INTRODUCTION: Although sporadic non-ampullary duodenal adenomas (SNADA) are rare, with the risk of progression to cancer, they deserve therapy. Endoscopic therapy of SNADA is effective, but with the increased risk of complications, endotherapy should be performed in high-volume units. The results of endotherapy of SNADA in our unit are presented. PATIENTS AND METHODS: A total of 97 patients with SNADA had endoscopic resection in 2005-2021 and control endoscopies between 3 and 24 months. Snare polypectomy, endoscopic mucosal resection (EMR), endoscopic band ligation (EBL) and endoloop were used (en bloc 37% and piecemeal 63%). In cases of residual/recurrent adenomas, endotherapy was repeated. RESULTS: The median size of the adenoma was 12 (5-60) mm and most polyps were sessile (25%) or flat (65%). Primary endotherapy eradicated adenomas in 57 (59%) cases. Residual and recurrence rates were 24% (n = 23) and 17% (n = 16) with successful endotherapy in 16 (70%) and 13 (81%) patients. Endotherapy was successful in 86 (89%) patients after a median (range) follow-up of 23 (1-166) months. Four out of 11 patients with failed endotherapy had surgery; seven patients were not fit for surgery. There were no disease-specific deaths or carcinoma. Eleven patients (11%) suffered from complications: perforation requiring surgery (n = 1), sepsis (n = 1), postprocedure bleeding (n = 7), cardiac arrest (n = 1) and coronary infarct (n = 1). The thirty-day mortality was zero. Colonoscopy was performed on 67 (69%) patients with neoplastic lesions in 33% patients during follow-up. CONCLUSIONS: Endotherapy of SNADA is effective and safe. Repeat endotherapy in residual and recurrent adenomas is successful. Careful patient selection is mandatory. Abbreviations: ASA: American Society of Anesthesiologist classification; BMI: body mass index; CT: computed tomography; EBL: endoscopic band ligation; EMR: endoscopic mucosal resection; ESD: endoscopic submucosal dissection; ET: endotherapy; FAP: familial adenomatous polyposis; F: female; LST: laterally spreading tumours; M: male; SD: standard deviation; SNADA: sporadic nonampullary duodenal adenoma.

Microsatellite instability in the high-grade dysplasia component of duodenal adenoma is associated with progression to adenocarcinoma.

PURPOSE: We examined the microsatellite instability of duodenal tumors to evaluate their molecular features associated with the adenoma-carcinoma sequence. METHODS: Fifty-two non-ampullary duodenal epithelial tumors collected by endoscopic mucosal resection or surgical resection were studied. When a tumor had two or more dysplasia grades, the highest grade was considered. Representative areas were macro-dissected and subjected to a microsatellite instability analysis and immunohistochemical staining. RESULTS: The 52 tumors were classified as either adenoma with low-grade dysplasia (n = 18), adenoma with high-grade dysplasia (n = 20), or adenocarcinomas (n = 14). Among these, 3 adenocarcinoma cases showed microsatellite instability and the remaining 49 tumors showed microsatellite stability. Of the 14 adenocarcinoma cases, 3 contained both high-grade dysplasia and adenocarcinoma components, and 11 contained only the adenocarcinoma component. Interestingly, all three adenocarcinoma + high-grade dysplasia cases were microsatellite instability-high in both the adenocarcinoma and high-grade dysplasia components. Immunohistochemical staining of mismatch repair proteins showed mismatch repair deficiency in three microsatellite instability-high adenocarcinoma + high-grade dysplasia cases. CONCLUSIONS: Only adenocarcinoma cases with high-grade dysplasia components were microsatellite instability-high (in both the adenocarcinoma and high-grade dysplasia components). This suggests that microsatellite instability in the high-grade dysplasia component of duodenal adenoma is associated with progression to adenocarcinoma.

Clip-guided local duodenectomy for safe and minimal local resection of nonampullary duodenal neoplasms.

BACKGROUND: Local duodenectomy and primary closure is a simple option for some nonampullary duodenal neoplasms. Minimizing the resection area while ensuring curability is necessary for safe primary duodenal closure. However, it is often difficult to determine the appropriate resection line from the serosal side. We developed clip-guided local duodenectomy to easily determine the resection range and perform local duodenectomy safely, then performed a retrospective observational study to confirm the safety of clip-guided local duodenectomy. METHODS: The procedure is as follows: placing endoscopic metal clips at four points on the margin around the tumor within 3 days before surgery, identifying the tumor extent with the clips under X-ray imaging during surgery, making an incision to the duodenum just outside of the clips visualized by X-ray imaging, full-thickness resection of the duodenum with the clips as guides of tumor demarcation, and transversely closure by Gambee suture. We evaluated clinicopathological data and surgical outcomes of patients who underwent clip-guided local duodenectomy at two surgical centers between January 2010 and May 2020. RESULTS: Eighteen patients were included. The pathological diagnosis was adenoma (11 cases), adenocarcinoma (6 cases), and GIST (1 case). The mean ± SD tumor size was 18 ± 6 mm, and the tumor was mainly located in the second portion of the duodenum (66%). In all cases, the duodenal defect was closed with primary sutures. The mean operation time and blood loss were 191 min and 79 mL, respectively. The morbidity was 22%, and all complications were Clavien-Dindo grade II. No anastomotic leakage or stenosis was observed. In the 6 adenocarcinoma patients, all were diagnosed with pT1a, and postoperative recurrence was not observed. The 1-year overall and recurrence free survival rate was 100%. CONCLUSIONS: Clip-guided local duodenectomy is a safe and useful surgical option for minimally local resection of nonampullary duodenal neoplasms such as duodenal adenoma, GIST, and early adenocarcinoma.

The conundrum in endoscopic management of duodenal polyps: a tertiary cancer center experience.

BACKGROUND: Endoscopic mucosal resection of duodenal polyps (EMR) is a challenging intervention. The aim of this study was to review the patient characteristics, techniques, procedure outcomes, adverse events, and recurrence of duodenal polyps. RESEARCH DESIGN AND METHODS: Patients were included if they had pathologically confirmed non-ampullary duodenal polyps and had received EMR with at least one follow-up EGD for surveillance. Descriptive statistics were employed to report the findings. RESULTS: A total of 65 patients underwent a total of 90 EMRs for duodenal polyps. The mean age was 65.4 years, and 29 of the patients were female. Complete resection of the visible mass was achieved in 96.9% of cases. Endoscopic hemostasis was required in 18.5% of patients. Delayed bleeding occurred in 9%, and delayed perforations requiring surgical intervention occurred in 2.2% of patients with no mortality. Surgery after EMR was needed in 12.7% of cases. Eleven (16.9%) patients had recurrent duodenal adenoma on follow-up EGD. CONCLUSION: Duodenal polyps can be safely resected and have a notable recurrence rate. This is particularly true for adenomas, warranting post-resection endoscopic surveillance. The appropriate interval for post-resection surveillance of duodenal adenomas should be a focus of future study.

Transduodenal resection for duodenal adenomas may be an underutilized tool - A single institution experience.

Background: Duodenal adenomas are pre-malignant lesions. Transduodenal resection and pancreaticoduodenectomy remain the only two surgical options. The optimal surgical management remains controversial between these two strategies. Methods: A retrospective review was conducted to identify patients who underwent intervention for duodenal adenomas. Patient were stratified by type of procedure, pancreaticoduodenectomy or transduodenal resection, and their demographic data as well as perioperative outcomes were compared. Results: 26 patients underwent surgery for duodenal adenomas. 11 underwent a pancreaticoduodenectomy (PD) (42.3%) and 15 underwent a transduodenal resection (TDR) (57.7%). Median operative time, median estimated blood loss, and mean length of stay were longer in the PD vs TDR group. Two patients (13.3%) in the TDR group developed recurrent adenomas. Conclusion: Transduodenal resection should be considered in patients who are suspected to harbor benign duodenal tumors. Duodenal tumors with high grade dysplasia or invasive cancer should undergo an oncologic procedure. Endoscopic surveillance appears to be indicated after transduodenal resection.

ESD-aid surgery as a new treatment strategy for duodenal adenoma.

OBJECTIVE: The treatment for nonampullary duodenal adenoma remains to have no consensus and established methods. Although endoscopic treatment is minimally invasive, it was reported to cause delayed perforation in more than 20% of cases. For adenomas in the duodenum, we performed endoscopic submucosal dissection (ESD)-aid surgery, which is a procedure to prophylactically suture the seromuscular structure of the duodenum after ESD. In this procedure, we did not perform Kocher mobilization prior to ESD to facilitate endoscopic resection and full-thickness resection to prevent spread of the tumor and infection to the abdominal cavity. The duodenal wall was reinforced in planes using a suture clip. RESULTS: Of the 13 cases of duodenal adenoma that underwent ESD-aid surgery at our hospital between April 2018 and December 2020, 1 developed postoperative bleeding, but there was no late perforation. For duodenal adenomas, ESD-aid surgery was considered a safe and minimally invasive treatment.

Prevalence and endoscopic treatment outcomes of upper gastrointestinal neoplasms in familial adenomatous polyposis.

BACKGROUND: Although upper gastrointestinal (GI) neoplasms are not rare in patients with familial adenomatous polyposis (FAP), few studies have focused on them and the long-term outcomes of their treatment by endoscopy. Therefore, we aimed to investigate the prevalence and endoscopic treatment outcomes of upper GI neoplasms in patients with FAP. METHODS: Among 215 patients diagnosed with FAP between January 1991 and December 2019, 208 who underwent esophagogastroduodenoscopy were eligible. The clinical features and endoscopic treatment outcomes of upper GI neoplasms were retrospectively investigated and analyzed. RESULTS: Among the enrolled patients, 113 (54.3%) had one or more upper GI neoplasms: gastric adenoma (n = 34), gastric cancer (n = 7), nonampullary duodenal adenoma (n = 86), and ampullary adenoma (n = 53). Among patients with gastric neoplasms (n = 37), 24 (64.9%) underwent treatment (endoscopic treatment: 22, surgery: 2). No tumor-related mortality occurred during median follow-up of 106 months (interquartile range [IQR] 63-174). Endoscopic treatment was performed in 47 (54.7%) of 86 patients with nonampullary duodenal adenoma and in 32 (60.4%) of 53 patients with ampullary adenoma. No patient underwent surgery for duodenal neoplasms, and no tumor-related mortality occurred during median follow-up of 88 months (IQR 42-145). The proportion of patients with increased Spigelman stage at 2 years after the initial diagnosis or treatment was significantly higher in untreated group than in the group treated for duodenal neoplasms (27.3% vs. 0.0%, p = 0.001). CONCLUSION: Endoscopic surveillance in FAP patients is important for the detection and treatment of upper GI neoplasms in early stage. In particular, endoscopic therapy for duodenal neoplasms can reduce the severity of duodenal polyposis.

Endoscopic Suturing for the Prevention and Treatment of Complications Associated with Endoscopic Mucosal Resection of Large Duodenal Adenomas.

BACKGROUND/AIMS: Endoscopic mucosal resection (EMR) is the primary treatment for duodenal adenomas; however, it is associated with a high risk of perforation and bleeding, especially with larger lesions. The goal of this study was to demonstrate the feasibility and safety of endoscopic suturing (ES) for the closure of mucosal defects after duodenal EMR. METHODS: Consecutive adult patients who underwent ES of large mucosal defects after EMR of large (>2 cm) duodenal adenomas were retrospectively enrolled. The OverStitch ES system was employed for closing mucosal defects after EMR. Clinical outcomes and complications, including delayed bleeding and perforation, were documented. RESULTS: During the study period, ES of mucosal defects was performed in seven patients in eight sessions (six for prophylaxis and two for the treatment of perforation). All ES sessions were technically successful. No early or delayed post-EMR bleeding was recorded. In addition, no clinically obvious duodenal stricture or recurrence was encountered on endoscopic follow-up evaluation, and no patients required subsequent surgical intervention. CONCLUSION: ES for the prevention and treatment of duodenal perforation after EMR is technically feasible, safe, and effective. ES should be considered an option for preventing or treating perforations associated with EMR of large duodenal adenomas.

Nonrecurrence Rate of Underwater EMR for ≤20-mm Nonampullary Duodenal Adenomas: A Multicenter Prospective Study (D-UEMR Study).

BACKGROUND AND AIMS: Endoscopic resection of nonampullary duodenal adenoma is often challenging, and its technique has not yet been standardized. To overcome the practical difficulty of conventional endoscopic mucosal resection, underwater endoscopic mucosal resection (UEMR) was recently developed; therefore, we investigated the effectiveness and safety of UEMR for nonampullary duodenal adenoma. METHODS: A multicenter, prospective cohort study was conducted at 21 institutions in Japan. We enrolled patients with no more than 2 nonampullary duodenal adenomas ≤20 mm in size, who were planned to undergo UEMR. After UEMR, follow-up endoscopies were scheduled at 2 and 12 months after the procedure, and biopsy specimens were taken from the post-UEMR scars. The primary endpoint was the proportion of patients with histologically proven nonrecurrence at follow-up endoscopy and biopsy. RESULTS: A total of 155 patients with 166 lesions underwent UEMR. One patient with a non-neoplastic lesion in the resected specimen and 10 patients with 10 lesions who were lost to follow-up were excluded. Finally, 144 patients with 155 lesions who received all follow-up endoscopies were analyzed for the primary endpoint. The proportion of patients with proven nonrecurrence was 97.2% (n = 140 of 144; 95% confidence interval, 92.8%-99.1%) which exceeded the predefined threshold value (92%). Two cases of delayed bleeding (1.2%) occurred and they were successfully managed by clips. All recurrences were successfully treated by additional endoscopic treatment. CONCLUSIONS: This multicenter, prospective cohort study demonstrated effectiveness and safety of UEMR for nonampullary duodenal adenomas ≤20 mm in size. (University Hospital Medical Network Clinical Trials Registry, Number: UMIN000030414).

Carbonic Anhydrases II and IX in Non-ampullary Duodenal Adenomas and Adenocarcinoma.

Non-ampullary duodenal adenocarcinoma (DAC) is a rare malignancy. Little information is available concerning the histopathological prognostic factors associated with DAC. Carbonic anhydrases (CAs) are metalloenzymes catalyzing the universal reaction of CO2 hydration. Isozymes CAII, CAIX, and CAXII are associated with prognosis in various cancers. Our aim was to analyze the immunohistochemical expressions of CAII, CAIX, and CAXII in normal duodenal epithelium, duodenal adenomas, and adenocarcinoma and their associations with clinicopathological variables and survival. Our retrospective study included all 27 DACs treated in Oulu University Hospital during years 2000-2020. For comparison, samples of 42 non-ampullary adenomas were collected. CAII expression was low in duodenal adenomas and adenocarcinoma. CAIX expression in adenomas and adenocarcinoma was comparable with the high expression of normal duodenal crypts. Expression patterns in carcinomas were largely not related to clinicopathological features. However, low expression of CAII associated with poorer differentiation of the tumor (p=0.049) and low expression of CAIX showed a trend for association with nodal spread, although statistical significance was not reached (p=0.091). CAII and CAIX lost their epithelial polarization and staining intensity in adenomas. CAXII expression was not detected in the studied samples. CAs were not associated with survival. The prognostic value of CAII and CAIX downregulation should be further investigated. Both isozymes may serve as biomarkers of epithelial dysplasia in the duodenum.

Case series of non-ampullary duodenal adenomas.

Duodenal adenomas are benign tumours of the duodenum which carry a malignant potential. They are found either sporadically or associated with familial syndromes. Majority of these cases are treated endoscopically but surgical resection is a better alternate to endoscopy in select cases. Endoscopic treatment is associated with higher chances of local recurrence and require frequent check endoscopies in the follow up period, while surgery offers a one-time treatment option. Identification of the ampulla and a duodenal resection sparing ampullary area becomes difficult in larger lesions of the 2nd part of the duodenum. Passage of a catheter from cystic duct through common bile duct to duodenum aids in identification of the ampullary area and is helpful in performing a local/wedge resection of the duodenum containing adenoma without injuring ampullary orifice.

APC mutations are common in adenomas but infrequent in adenocarcinomas of the non-ampullary duodenum.

BACKGROUND: Recent studies highlighted the clinicopathological heterogeneity of non-ampullary duodenal adenomas and adenocarcinomas, but the detailed process of the malignant transformation remains unclear. METHODS: We analyzed 144 adenomas and 54 adenocarcinomas of the non-ampullary duodenum for immunohistochemical phenotypes, genetic alterations, and mismatch repair (MMR) status to probe their histogenetic relationship. RESULTS: The median ages of patients with adenoma and adenocarcinoma were the same (66 years). Adenomas were histologically classified as intestinal-type adenoma (n = 124), pyloric gland adenoma (PGA, n = 10), gastric-type adenoma, not otherwise specified (n = 9), and foveolar-type adenoma (n = 1). Protein-truncating APC mutations were highly frequent in adenomas (85%), with the highest prevalence in intestinal-type adenomas (89%), but rare in adenocarcinomas (9%; P = 2.1 × 10-23). Close associations between phenotypic marker expression and genetic alterations were observed in adenomas, but not in adenocarcinomas, excluding the common association between GNAS mutations and MUC5AC expression. MMR deficiency was more frequent in adenocarcinomas (20%) than in adenomas (1%; P = 2.6 × 10-6). One MMR-deficient adenoma and three MMR-deficient adenocarcinomas occurred in patients with Lynch syndrome. Additionally, three other patients with an MMR-deficient adenocarcinoma fulfilled the revised Bethesda criteria. CONCLUSION: The discrepant APC mutation frequency between adenomas and adenocarcinomas suggests that APC-mutated adenomas, which constitute the large majority of non-ampullary duodenal adenomas, are less prone to malignant transformation. Non-ampullary duodenal adenocarcinomas frequently exhibit MMR deficiency and should be subject to MMR testing to determine appropriate clinical management, including the identification of patients with Lynch syndrome.

Endoscopic mucosal resection of sporadic duodenal nonampullary adenoma: outcomes of 130 patients with a long-term follow up in two tertiary French centers.

BACKGROUND: The long-term outcomes and safety of endoscopic mucosal resection (EMR) of sporadic duodenal adenoma (SDA), and the management of adverse events need to be confirmed. METHODS: A bicentric retrospective study was performed including all patients who underwent EMR for SDAs from 2003-2016. The primary aim was to evaluate the efficiency of EMR for SDA. The secondary objectives were to assess safety, recurrence management, predictive factors for treatment success, and adverse events. RESULTS: One hundred thirty patients (134 procedures) were included (median age 65 years, 49.3% male). The mean SDA size was 20.7 (range 5-50) mm. Of the SDAs, 58.2% were category 3 of the Vienna classification, 35.8% were category 4, and 5.9% were category 5. The median follow up was 25.0 (range 2-120) months. Complete mucosal resection was achieved for 129/134 lesions (96.2%), with en bloc resection in 59/134 (44%). Recurrence occurred in 28.6% of cases (30/105 procedures). Recurrence was successfully treated by new endoscopic procedures in 72.2% (13/18) and by surgery in 27.8% (5/18). Delayed bleeding occurred in 13.4% of cases (18/134) and was successfully managed endoscopically. The perforation rate was 3.7% (5/134); perforations were managed without surgery in 60% (3/5 patients) of cases. CONCLUSIONS: Endoscopic treatment of SDA appears to be effective and relatively safe in tertiary centers. All bleeding complications were endoscopically controlled, and perforation was rare. Recurrence was frequent but could be managed endoscopically. EMR is confirmed as a first-line treatment in cases of SDA, and surgery is useful only if repeated EMRs fail.