and metastases. These findings indicate that naturally occurring SST may at least be partlyresponsible for the generally slow growth rate of SI-NETs.Protein expression (IHC) vs. mRNA expression (ISH)

A. SI-NETs: Ki-67 index ,1% vs. .1%. B. Primary SI-NETs vs. Liver Mets

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19-Year Single Center Experience in the Management of Patients With PrimaryGastrointestinal (GI) LymphomaWolfgang Fischbach, Nicole Müller

Introduction: Primary GI lymphoma are a rare disease. Multicenter studies were, therefore,initiated in the 90ies with various published results in subgroups of GI lymphoma. We herereport our long-term findings in patients with any primary GI lymphoma who were nottreated within a controlled clinical trial. Method: As a German reference center patients withGI lymphoma are regulary presented to our institution. From 1993 on, we saw 102 consecu-tive patients (59 male and 43 female, age 31-89 years) with primary GI lymphoma: gastricMALT lymphoma = 76 (63 stage I, 6 stage II, 7 stage III/IV); secondary high grade MALTlymphoma = 3; diffuse large B-cell lymphoma (DLBCL) = 14 (Stage I/II/III-IV = 8/4/2);Burkitt lymphoma = 1; intestinal follicular lymphoma (FL) grade I/II = 8 (stage I/II/III-IV =5/1/2). Treatment strategies were as follows:MALT-lymphoma: H. pylori eradication, radiation(RTx) and/or chemotherapy (CTx) in stages . II or in case of eradication failure; DLBCL:CTx except in 3 cases treated by H. pylori eradication only; FL: no therapy, CTx or RTx.Results: 26/47 patients (55%) with MALT lymphoma achieved complete remission (CR)after exclusive H. pylori eradication. Application of all therapeutic procedures resulted inCR = 53/76 (70%) and PR with watch-and-wait = 22/76 (29%). There was only 1 patientrevealing progression. In DLBCL, 12 (86%) achieved CR after 1-3 line therapies. In FL,watch-and-wait resulted in long-term stable disease in n=5, CR after RTx in 1 case, andstable disease after CTx in 2 cases. Conclusion: Despite a negative selection of patients beingpresented to our reference center the overall treatment results in all subgroups of GI lym-phoma are excellent when all treatment options are offered in a sequential therapy strategy.Watch-and-wait is a promising approach in MALT lymphoma with residual disease followingH. pylori eradication and in FL.

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Gastrointestinal Stromal Tumors Show Strong Association With Synchronousor Metachronous Other MalignanciesRicha Jain, Ihab Lamzabi, Paolo Gattuso, Shriram Jakate

Background: Gastrointestinal stromal tumor (GIST) is the most common malignant mesen-chymal tumor of the GI tract. GISTs most commonly develop from mutations in KIT (80-85%), less often in PDGFRA (5-10%) and rarely from other sites. While germline mutationsoccur rarely, the overwhelming majority of these mutations are somatic, in which settingmulti-organ cancers are less likely to occur. We reviewed GIST cases from last 19 years toevaluate association of GIST with other malignancies. Design: From our Medical Center'spathology and clinical databases we retrieved 103 cases of C-kit positive GISTs from 1993-2011 (Female:54, Male:49; mean age 63). We investigated if these patients had othermalignancies that occurred synchronously or metachronously. We also assessed the distribu-tion of second malignancies and their relationships if any with the location, size and highmitoses (.10/50 hpf) of GIST. Results: 62/103 (60%) of GISTs were located in the stomach(mean size 2.9 cm) followed by small bowel (27/103 or 26%, mean size 6.3 cm). Only 9/103 cases had highmitoses. 42/103 (40%) cases had other malignancies, the majority of which(27/42 or 64%) were gastrointestinal carcinomas and occurred synchronously (colorectal6/27, gastric 5/27, distal esophageal 4/27). In 15/42 cases, other malignancies occurredmetachronously, most of which (12/15) preceded GIST by mean of 1.2 years and the

S-759 AGA Abstracts

majority were breast carcinomas (6/15). GISTs associated with other malignancies showedno differences in location, size and mitoses compared with GISTs without other malignancies.Conclusions: GISTs show high incidence (40%) of other malignancies despite known pre-dominant somatic and not germline mutations. The majority of other malignancies occursynchronously and are gastrointestinal carcinomas. Metachronously occurring GISTs aremost often preceded by breast carcinomas, often within 2 years. The rate of second malignan-cies appears to be sufficiently high to consider surveillance studies (colonoscopy and esopha-gogastroduodenoscopy, mammography) and genetic studies for additional undiscoveredmutations.

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Nonsurgical Treatment for Intestinal Follicular Lymphoma: A RetrospectiveAnalysis of 43 PatientsShotaro Nakamura, Takayuki Matsumoto, Koji Ikegami, Ema Washio, Motohiro Esaki,Keisuke Kawasaki, Koichi Kurahara, Minako Hirahashi, Takanari Kitazono, MakotoHashizume

Background: Double-balloon endoscopy (DBE) and capsule endoscopy (CE) have increasedthe detection of the jejunoileal lesions of intestinal follicular lymphoma (FL). However,optimal therapeutic strategy for this disease has not been established. Methods: The clinico-pathologic features and efficacy of nonsurgical treatments of intestinal FL were retrospectivelyanalyzed in 43 Japanese patients (21 men and 22 women; median age, 60 years). In allpatients, DBE and/or CE were performed. The presence of t(14;18)/ IgH-BCL2 was determinedby fluorescence in situ hybridization. Results: The site of the involvement was the duodenum(84%), the jejunum (74%), the ileum (51%), and the colorectum (19%). Involvement ofmultiple segments of the gastrointestinal (GI) tract was found in 81%. Macroscopically, 91%of cases showed polyposis type. The histologic grade 1-2 was seen in 93% of cases, whilet(14;18) was detected in 95%. Clinical stage by Lugano classification was as follows; stageI in 25 patients, stage II1 in 2, stage II2 in 4, stage IIE in 2 and stage IV in 10. Initialtreatment modalities included watch and wait/antibiotics (n=13), rituximab monotherapy(R alone group; n=18), and rituximab plus chemotherapy (R-CHOP group; n=12). Completeremission (CR) of FL was achieved in 27 patients (63%) and partial remission in 7 (16%),while 9 patients (21%) showed no change. During the follow-up periods ranging from 0.5to 8.0 years (median 3.3 years), one patient died of causes unrelated to FL, while 11 (26%)showed relapse or progression of FL. The progression-free survival (PFS) rate after 3 and5 years was 81% and 59%, respectively. Patients with involvement of multiple GI segmentstended to have worse PFS than those of single segments ( P=0.054). Patients with stage II-IV were less frequent in R alone group (28%) than in R-CHOP group (92%). After thetherapy, CR was achieved in 78% in R alone group, while in 100% in R-CHOP group ( P=0.13). The relapse/progression equally occurred (both 33%), and the PFS rate after 3-yearsdid not differ between R alone (65%) and R-CHOP groups (82%, P=0.75). Conclusions:Intestinal FL frequently involves the duodenum and the jejunum. Therefore, assessment ofsmall bowel using DBE and/or CE is mandatory. Both rituximab monotherapy and R-CHOPtherapy are effective. Careful follow-up is required especially for patients who have FL inthe multiple GI portions.

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EUS Guided Keyhole Biopsy: Simple and Successful Histologic Diagnosis ofSubmucosal GI TumorsPeter Grubel

BACKGROUND: EUS guided FNA is often hampered by the lack of sufficient tissue to allowhistology and immunohistochemistry and Tru-Cut biopsy is technically difficult when theendoscope is angulated. EUS guided keyhole biopsy technique (EUS-KB) is a novel techniqueto sample submucosal tumors (SMT). METHODS: Patients with SMT were prospectivelyexamined over a 2-year period. Following EUS evaluation, a needle knife was used to cuta small mucosal keyhole over the center of the lesion (A). A biopsy forceps was thenintroduced through the hole into the center of the lesion and samples were obtained andplaced in formalin (B). RESULTS: 23 patients (mean age 69 years) with SMT underwentEUS-KB. The anatomic sites of the lesions were as follows: Esophagus in 1, stomach in 16,duodenum in 5, and rectum in 1 patient. The mean procedural time was 21 minutes.There was one bleeding complication (4%) controlled with epinephrine injection. Adequatespecimens for histology, mitotic rate and immunohistochemistry were obtained in all patientsallowing a diagnosis in all patients. The tissue specimens measured 2-15 mm and showedno cautery artifacts. Pathology showed 14 benign lesion and 9 neoplastic lesions (8 GIST,1 gastrinoma). Surgical resection was performed in three patients and confirmed the EUS-KB diagnosis of GIST and gastrinoma. CONCLUSIONS: EUS-KB is an easy, quick and safetechnique. It provides abundant histological tissue to accurately diagnose SMT.

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