Sa1090 Management of Non-Ampullary Duodenal Adenomas in Patients With Familial Adenomatous Polyposis (FAP) and Non-FAP Patients: Should We Manage Them Differently? Lisa S. Cassani, Gandhi Lanke, Patrick M. Lynch, Christopher Chan, Jeffrey Lee Background: Non-ampullary duodenal adenomas are either sporadic or associated with a hereditary syndrome such as familial adenomatous polyposis (FAP). Duodenal adenomas are common in this syndrome, found in approximately 80 to 90% of patients. Objective: The aim of this study is to compare characteristics of sporadic and FAP-associated duodenal adenomas. Methods: This study was approved by the institutional review board. This was a retrospective review at a single center tertiary care institution. Subjects were identified from a pathological database. Subjects with ampullary adenomas only and with less than 2 month follow up were excluded. Data were obtained via review of medical records. Results: A total of 213 subjects were identified. Of those subjects, 117 subjects had FAP and the remainder were considered sporadic. Median age at diagnosis was 40 and 67 for subjects with FAP-associated adenomas and sporadic adenomas, respectively (P<0.0001). Length of follow up was 75±67 months for FAP subjects and 31±30 months for subjects with sporadic adenomas. At time of last follow up, 87.2% of those patients with FAP-associated adenomas had undergone colectomy versus 13% in the sporadic group. 52.1% of had ampullary involvement in addition compared to 7.3% in those subjects with sporadic adenomas (P<0.0001). FAP subjects were more likely to have multifocal disease within the duodenum (69% vs 33%, P<0.0001). On average FAP subjects underwent 6.5 endoscopies during the follow up period, and those with sporadic adenomas underwent 5.3 endoscopies. On initial pathology, there were 71 tubular adenomas (TA) and 46 tubulovillous adenomas (TVA), 15 of which had dysplasia (4 with low grade dysplasia (LGD) and 12 with high grade dysplasia (HGD)), within the FAP group. There were 48 TAs, 47 TVAs, and 1 villous adenoma, 14 of which had dysplasia (2 with LGD and 12 with HGD), in the sporadic group. 14 of 117 (12%) with FAP and 33 of 96 (34%) subjects with sporadic duodenal adenomas underwent endoscopic mucosal resection (EMR). Histologic progression to dysplasia or cancer was seen in 27 (23%) subjects with FAP and 13 (14%) with sporadic disease (P= 0.08). 6 patients within the cohort progressed to cancer, 2 within the FAP group and 4 within the sporadic group. Range of time to progression in those with cancer was 3 to 161 months. Median time to progression was 99.0 months in the FAP group and 122.2 months in the sporadic group. Conclusions: Those patients with FAP were significantly younger, more likely to have ampullary involvement, and more likely to have multifocal disease. Median time to progression to dysplasia or cancer as well as percent of subjects who progress is similar among FAP-associated and sporadic adenomas. Progression to cancer is infrequent, however unpredictable, and an interval for surveillance cannot be recommended given the current data. S-221 AGA Abstracts Sa1091 Open Biopsy Is a Safe and Effective Method for Diagnosing Submucosal Tumors of the Digestive Tract Shigeto Koizumi, Mario Jin, Tamotsu Matsuhashi, Natsumi Hatakeyama, Reina Ohba, Kengo Onochi, Shin Tawaraya, Masayuki Sawaguchi, Noboru Watanabe, Noriyoshi Kanazawa, Yusato Suzuki, Mitsuaki Ishioka, Hirosato Mashima, Hirohide Ohnishi [Background and Aim] Although endoscopic ultrasound guided fine-needle aspiration (EUS- FNA) is a useful tool for diagnosing submucosal tumors (SMTs) of the digestive tract, EUS- FNA sometimes fails to obtain adequate specimens for the pathological diagnosis. Further, some locations and small sizes of the SMTs make EUS-FNA difficult. In addition, EUS-FNA has the risk of the injury to the surrounding organs. Therefore, we hypothesized that open biopsy can be another useful method for the pathological diagnosis of SMTs. We thus examined the efficiency and safety of the open biopsy for the diagnosis of SMTs of the digestive tract. [Methods] Between 2011-2014 at Akita University Hospital, 10 cases of SMTs (esophagus: 3 cases, stomach: 5 cases, sigmoid colon: 1 case, rectum: 1 case) underwent open biopsy. We enrolled these 10 cases and evaluated tumor size, procedure time, the number of the obtained biopsy specimens, tumor sampling rate and complication rate. Typically, open biopsy was carried out as follows. First, saline was injected into the submuco- sal layer at the top of the SMT, then the mucosal and submucosal layers were incised with a needle-knife in order to expose the surface of the SMT. After that, the tumor tissue was obtained from the exposed surface of the SMT with a biopsy forceps. [Results] All 10 cases were pathologically diagnosed by open biopsy successfully. The findings were; 2 cases were leiomyoma of the esophagus, 1 case was epithelioid granuloma of the esophagus, 4 cases were gastrointestinal stromal tumor of the stomach, 1 case was leiomyoma of the stomach, 1 case was lipoma of the sigmoid colon and 1 case was metastatic rectal cancer (poorly differentiated adenocarcinoma, origin unknown). The average size of tumors was 39.5mm and the average procedure time was 29.0 minutes. Median number of the biopsy specimens was 6 specimens (4-8). Tumor sampling rate (number of biopsy specimens including tumor tissue / total number of biopsy specimens) was 96.9%. No major complications occurred. Although intra-luminal minor bleeding was observed in 2 cases after open biopsy, it was well controlled conservatively in both cases. [Conclusion] Open biopsy is a safe and effective method for the pathological diagnosis of SMTs of the digestive tract. Sa1092 Tissue-Engineered Cell Sheets From Oral Mucosal Epithelial Cells Exhibit Good Viability and Proliferative Activity Sebastian Sjöqvist, Peter Elbe, Eduard Jonas, Pontus Blomberg, Jenny Enger, Katrin Markland, Makoto Kondo, Mei Ling Lim, Rainer Heuchel, J. Matthias Löhr Introduction Stricture formation after extensive endoscopic submucosal dissection (ESD) remains a major clinical problem. It has previously been shown that transplantation of autologous cell sheets could improve esophageal mucosal healing and possibly reduce stricture formation. The purpose of this study is to investigate the properties of the tissue engineered cell sheets prior to transplantation in patients. Aims and Methods Oral mucosal biopsies and blood samples were taken from 10 patients. Under good manufacturing practice AGA Abstracts