Prior Colonoscopy Research Articles

Three-dimensional reconstruction of computed tomography colonography discloses anatomic features associated with colonoscopy failure.

Three-dimensional virtual reality (3D VR) permits precise reconstruction of computed tomography (CT) images, and these allow precise measurements of colonic anatomical parameters. Colonoscopy proves challenging in a subset of patients, and thus CT colonoscopy (CTC) is often required to visualize the entire colon. The aim of the study was to determine whether 3D reconstructions of the colon could help identify and quantify the key anatomical features leading to colonoscopy failure. Retrospective observational study. Using 3D VR technology, we reconstructed and compared the length of various colonic segments and number of bends and colonic width in 10 cases of CTC in technically failed prior colonoscopies to 10 cases of CTC performed for non-technically failure indications. We found significant elongation of the sigmoid colon (71 ± 23 cm versus 35 ± 9; p = 0.01) and of pancolonic length (216 ± 38 cm versus 158 ± 20 cm; p = 0.001) in cases of technically failed colonoscopy. There was also a significant increase in the number of colonic angles (17.7 ± 3.2 versus 12.7 ± 2.4; p = 0.008) in failed colonoscopy cases. Increased sigmoid and pancolonic length and more colonic bends are novel factors associated with technical failure of colonoscopy.

Post-Colonoscopy Colorectal Cancer Etiologies in a Large Integrated US Health Care Setting

Post-Colonoscopy Colorectal Cancer Etiologies in a Large Integrated US Health Care Setting

Endoscopist Characteristics and Polyp Detection in Colonoscopy: Cross-Sectional Analyses of Screening of Swedish Colons

Endoscopist Characteristics and Polyp Detection in Colonoscopy: Cross-Sectional Analyses of Screening of Swedish Colons

S284 Family Matters: Impact of a Dot Phrase on Complete Family History Documentation During Initial Colorectal Cancer Screening Visits

Introduction: Obtaining a complete family history (FH) informs gastrointestinal (GI) cancer screening and referrals for genetic testing, but this is inconsistently done during colorectal cancer (CRC) screening visits. Previously, we improved the rate of complete FHs obtained to 28.4% from 5.2% after implementing education and a FH screening form in clinic. In this study, we assessed the impact of sharing a FH dot phrase on the rate of complete FHs obtained and genetics referrals made during outpatient CRC screening visits. Methods: We shared a dot phrase that prompts obtaining a complete FH to our gastroenterology division on February 9, 2022. A complete FH was defined as addressing history of cancer in first- and second-degree relatives, colon polyps in first-degree relatives, and GI disease. We reviewed outpatient GI CRC screening visits from February 10, 2022 to March 9, 2022, and compared them to a one-month period of pre-intervention visits. Patient characteristics, rates of complete FH and genetic referrals were extracted. Patients with prior colonoscopies or indications for diagnostic colonoscopy were excluded. Rates of complete FH and genetic referrals were compared between the pre- and post-intervention groups with unpaired T-tests. Results: A total of 188 patient visits were included; 93 post-intervention and 81 pre-intervention. The pre-and post-intervention groups were overall similar, but there were more white patients in the post-intervention group (Table). Complete FHs were obtained in 46/93 (49.5%) of post-intervention visits compared to 23/81 (28.4%) of visits in the pre-intervention group (p = 0.004). Genetic referrals were placed in 1/93 (1.1%) of post-intervention visits compared to 3/81 (3.7%) of pre-intervention visits (p=0.270). Conclusion: In our study, the rate of complete FHs obtained increased significantly to 49.5% from 28.4% after introduction of a FH dot phrase . The rate of genetic referrals was unchanged, though a larger sample size may be required to detect any potential difference. Given there were more white patients in the post-intervention group, further observation of complete FH rates in patients based on race is warranted. When upper GI problems were addressed along with CRC screening, FHs were often incomplete, suggesting a target for further intervention. Overall, further efforts are warranted to increase the rate of complete FHs obtained during CRC screening visits. Table 1. - Baseline characteristics and statistical analyses Patient Characteristics Whole CohortN=174 Pre-interventionN= 81 Post-interventionN= 93 p value Average age at screening, standard deviation [years] 51 51 50 Gender, n (%) Male 75 (43%) 33 (41%) 42 (45%) 0.1416 Female 99 (57%) 48 (59%) 51 (55%) 0.6672 Race/Ethnicity, n (%) AA 85 (49%) 44 (54%) 41 (44%) 0.6455 Asian 9 (5%) 3 (3.7%) 6 (6.5%) 0.1585* Hawaiian or Pacific Islander 0 (0%) 0 (0.0%) 0 (0%) - Hispanic 12 (6.9%) 5 (6.2%) 7 (7.5%) 0.4122 Other 8 (4.6%) 5 (6.2%) 3 (3.2%) 0.3173* Unknown 11 (6.3%) 7 (8.6%) 4 (4.3%) 0.2005* White 49 (28%) 17 (21%) 32 (34%) 0.0024 Complete family history 69 (40%) 23 (28.4%) 46 (49.5%) 0.004 Genetic referral 3 (1.7%) 3 (3.7%) 1 (1.1%) 0.2695 *High estimated error, category with value less than 5.

S2791 A Rare Etiology for Ulcerative Colitis Flare

Introduction: Prior to colonoscopy, it is well understood that patients must undergo bowel cleansing. Based on the type of laxative, colonoscopy preparations fall into two categories – polymer-based formulas (PEG) and saline-based formulas (NaP). Both types of bowel preparations are deemed to be relatively safe and part of routine practice. However, we describe the rare case of an ulcerative colitis (UC) flare due to the bowel preparation formula. Case Description/Methods: A 29-year-old female with diagnosis of UC, presently in clinical and biochemical remission on oral mesalamine, contracted COVID-19 and had reactivation of UC symptoms. After being on budesonide tablets and rectal foam for two months, patient achieved clinical remission, and a surveillance colonoscopy was performed which revealed normal colon and terminal ileum except mild congestion in the cecum (Figure A). Pathology revealed unremarkable mucosa in the entire colon except for chronic active colitis in the cecum. Immediately following this colonoscopy, the patient started to experience another severe UC flare requiring hospitalization. The patient’s laboratory work-up was normal except for an elevated fecal calprotectin (1710). Stool infectious work-up was negative and the patient denied any NSAID or antibiotic use. The patient underwent a repeat colonoscopy which revealed severe Mayo 3 pancolitis (Figure B) in comparison to a stable colonoscopy a few weeks prior. It was revealed that for her initial colonoscopy, she had used SUPREP bowel prep kit. On prior colonoscopies she had used MiraLAX bowel prep with no adverse effects. During hospitalization, the patient was started on biologic therapy with good effect. Discussion: There are no clear guidelines on appropriate bowel preparation formula for the inflammatory bowel disease (IBD) population. Sufficient literature exists to confirm that NaP can irritate the intestinal mucosal wall. Moreover, numerous animal experiments have employed dextran sodium sulfate for chemical induction of intestinal inflammation to mimic UC flares in humans [1]. Thus, it can be surmised that because SUPREP ingredients contain sodium sulfate, the potential for UC flare is higher. It is pertinent for practitioners to be aware of the possible rare adverse effects of saline-based formulas, especially when treating the IBD population.Figure 1.: (A) Colon (04/19/2022) and (B) Colon (05/09/2022).

S2084 An Unusual Cause of Rectal Bleeding: Colonic Angiolipoma

Introduction: Angiolipomas are rare, benign, subcutaneous tumors composed of adipose tissue and vascular components. Angiolipomas are extremely rare in the colon, accounting for less than 1% of all colonic benign lesions. While these tumors are typically painful, they may also present with rectal bleeding or positive fecal occult blood test in an otherwise asymptomatic patient. Therefore, it is important to recognize the clinical, radiological, and endoscopic findings associated with these masses. Case Description/Methods: A 49-year-old male with hypertension and hyperlipidemia presented for evaluation of 3 days of self-limited rectal bleeding. The patient had no prior colonoscopies and denied associated symptoms of abdominal pain, diarrhea, or constipation. On physical examination, the abdomen was soft, non-tender, and non-distended with no palpable masses. Colonoscopy was remarkable for a malignant-appearing, large, ulcerated, non-bleeding mass in the hepatic flexure (Figure 1). Biopsy of the mass demonstrated features of focal active colitis and erosion without evidence of dysplasia or malignancy. The patient was referred to oncology for further evaluation of the mass. Positron emission tomography-computed tomography (PET-CT) results were remarkable for abnormal thickened appearance of the colon at the hepatic flexure with an adjacent 4.4 cm fatty structure in the proximal transverse colon without fluorodeoxyglucose radiotracer uptake. The patient was evaluated by colorectal surgery and received a robotic-assisted laparoscopic right colectomy with an isoperistaltic ileotransverse colon anastomosis. The specimen was sent to pathology and results demonstrated a 4.4 × 4.0 × 4.0 cm protruding mass with glanular mucosa and submucosal fatty cut surfaces, consistent with angiolipoma. Immunohistochemical (IHC) staining was unremarkable for angiomyolipoma. The patient tolerated the procedure well without significant sequelae. Discussion: Angiolipomas are typically painful yet benign tumors that are rarely found in the gastrointestinal tract. Although abdominal pain, rectal bleeding, and/or positive fecal occult blood testing are commonly reported on presentation, diagnosis is complicated as symptoms tend to be non-specific. Preoperative diagnosis of angiolipoma is possible when aided by CT, endoscopy, and MRI, but surgical pathology remains the gold standard for final diagnosis of the tumor. When angiolipomas are fully excised, the prognosis is excellent.Figure 1.: Endoscopic identification of malignant-appearing mass in hepatic flexure.

S2484 ColoWrap Device Facilitates Successful Colonoscopy in Patient With Prior Incomplete Colonoscopy Due to Looping and Adhesions

S2484 ColoWrap Device Facilitates Successful Colonoscopy in Patient With Prior Incomplete Colonoscopy Due to Looping and Adhesions

S2269 Malignant Dysphagia in Latent Triple Negative Metastatic Breast Cancer

Introduction: Luminal gastrointestinal metastasis of breast cancer is rare and esophageal metastasis from breast cancer is reported in less than 100 cases. We present a unique case of metastatic esophageal cancer from a primary breast malignancy, 20 years post initial diagnosis. Case Description/Methods: A 79-year-old African American female with past medical history of triple negative metastatic breast cancer, COPD, HTN, & T2DM presented to the hospital with 3 weeks of progressive dysphagia to liquids & solids, regurgitation and 10kg weight loss. No heartburn, nausea/vomiting or change in bowel habits. No prior EGD and colonoscopy many years ago showed 2 benign polyps. She was diagnosed with breast cancer in early 2000s and underwent right mastectomy; recurrence was discovered in 2014, which led to lumpectomy, chemotherapy/radiation. Vital signs stable on arrival. Physical examination notable for cachectic female; no lymphadenopathy, abdominal distension/tenderness or edema. Labs showed: WBC 7.9, Hb 11, MCV 82, Plt 291. EGD, showed severe stenosis in the mid-esophagus – dilation was attempted, but unsuccessful; biopsies were negative. Esophogram revealed severe stenosis of the mid-esophagus. CT thorax demonstrated a focal density in the mid-esophagus & multiple hepatic lesions concerning for metastasis. Endoscopic ultrasound (EUS) revealed severe stenosis of mid-esophagus; dilation, fine needle aspiration (FNA) and stent placement were performed. Pathology demonstrated metastatic triple negative breast cancer. The patient planned to start paclitaxel but was placed on hospice (Figure). Discussion: Esophageal metastasis of breast cancer has a prevalence of 0.59-5.9%. The most common presenting symptom is dysphagia. Studies describe a latency period between the diagnosis of breast cancer and symptoms of esophageal metastasis. Diagnosis is difficult as mucosal involvement is rare and most cases will present with stricture and normal mucosa. EUS with FNA is necessary to confirm diagnosis. Some success has been shown with expandable stents for symptomatic relief as dilation is limited by high risk of perforation. As in our case, esophageal metastasis is usually part of multi-organ metastasis, so treatment aimed at the primary malignancy, but palliative in most cases. Concern for malignant dysphagia must be included in the differential for breast cancer patients presenting with dysphagia. Due to difficult diagnosis and latency period, more routine screening with EUS may be beneficial.Figure 1.: Repeat EGD with EUS & Fluoroscopic guided stent placement.

S2292 Dysphagia and Esophageal Mass: Cancer or Actinomycosis?

Introduction: Esophageal actinomycosis is a rare type of esophageal infection and presents as erosions or ulcers under endoscopy. Here we present a 63-year-old woman who complains of dysphagia, with biopsy showing actinomyces infection but repeat biopsy revealed squamous cell carcinoma. Case Description/Methods: A 63-year-old Chinese female with a history of gastritis presented with solid food dysphagia and epigastric pain for over a month. The pain was not improved after proton pump inhibitors but was relieved by self-induced vomiting. Review of systems showed 10lb weight loss over a month with a recent history of self-resolved hematemesis. Prior esophagogastroduodenoscopy (EGD) and colonoscopy were normal 3 years ago. CT of the chest demonstrated a 1.7 cm circumferential mass in the mid-esophagus with luminal narrowing (Figure 1A). EGD discovered a friable soft circumferential mass 26-29 cm from the incisors that are not actively bleeding but covered with blood clots (Figure 1B). Biopsy showed esophageal mucosal ulceration and actinomyces infection. The patient was started on amoxicillin to treat actinomyces infection. Meanwhile, the patient underwent a repeat EGD for rebiopsy given concerns for malignancy, which resulted in poorly differentiated squamous cell carcinoma. Endoscopic ultrasonography (EUS) was performed for staging but was limited staged uT3N1Mx as the mass could not be traversed by echoendoscopy (Figure 1C). Later PET-CT illustrated locally advanced disease with atrium involvement (Figure 1D). The patient underwent neoadjuvant chemotherapy with carboplatin-taxol and radiation followed by esophagogastrectomy for curative intent. Discussion: Actinomyces are facultatively anaerobic, Gram-negative bacilli. They commensally live within the oral cavity and gastrointestinal tract. Most esophageal actinomyces (EA) infection was previously described to resemble esophagitis or esophageal ulcers, with the endoscopic description being extensive necrotic areas. EA typically presents with dysphagia and odynophagia, particularly in immunocompromised patients or with malignancies. Actinomyces species capitalize on tissue injury or mucosal breach to invade adjacent structures and spreads regardless of anatomical barrier, thus mimicking malignancy. In our case, the local tissue damage caused by neoplastic disease or irradiation predisposed the actinomyces infection. Clinicians need to have a high index of suspicion and clinical knowledge regarding its unusual presentations and ability to mimic malignancy.Figure 1.: A. CT of the chest demonstrated a 1.7 cm mass present in the mid-esophagus with lumen narrowing. B. A friable mass without active bleeding but covered with blood clots on endoscopy finding. C. Limited staged uT3N1Mx under EUS D. PET-CT showed locally advanced disease with atrium involvement.

S3409 Features of Recurrent Mechanical Obstruction With Nonobstructive Duodenal Neuroendocrine Tumor

Introduction: Neuroendocrine tumors (NET) are a rare cause of bowel obstruction which is usually mechanical in nature. We present an unusual case of bowel obstruction in a patient with NET where no mechanical obstruction was found despite extensive work up. Case Description/Methods: A 56-year-old male was admitted after 9-10 admissions to another facility with bowel obstruction and 50-pound weight loss over 10 months. His symptoms included abdominal pain, distention, and vomiting. He had no prior abdominal surgeries. Previous CT abdomen revealed small bowel obstruction with transition point in the terminal ileum. Current CT showed gastric outlet obstruction (Figure A). Formerly he was managed nonoperatively with nasogastric tube (NGT) decompression. Prior esophagogastroduodenoscopy and colonoscopy did not reveal an obstruction. NGT output was 2.5 L. Push enteroscopy, video capsule endoscopy did not reveal any mechanical obstruction. MR enterography showed two right mesenteric nodules, larger of which was 2.1 x 2.3 cm in size. These were moderately FDG avid on PET-CT. Endoscopic ultrasound biopsy revealed a well differentiated NET. The lesions were intensely somatostatin receptor positive on Gallium-68 DOTATOC PETCT (Figure 1B). Pancreatic polypeptide was 2145 pg/mL (0-435), chromogranin A 1458 ng/ml (0-103), serotonin 278 ng/mL (50-200), and gastrin 208 ng/mL (0-100). He underwent partial duodenal resection with primary repair and peripancreatic lymph node resection. No obstructive pathology was found intraoperatively. Histopathology confirmed well differentiated NET with metastatic peripancreatic nodes. He has had no admissions over the past 3 months and has gained 33 pounds. Discussion: NET are rare tumors and use of appropriate diagnostic modalities are key to timely diagnosis. Despite improvement and availability of diagnostic modalities, most patients have metastatic disease at diagnosis. NET presenting with bowel obstruction usually have an obstructing tumor. We wish to bring to light the unusual presentation of NET with mechanical obstruction on imaging but extensive negative work up for an actual obstructing lesion. It is possible that mesenteric inflammation and edema secondary to NET may have caused recurrent obstruction in this case. NET can present with mechanical obstruction and are often missed on conventional imaging. Gallium-68 DOTATOC PETCT may be a reasonable investigation in a patient with unexplained recurrent gastrointestinal obstruction.Figure 1.: A, CT abdomen with dilated stomach and duodenum and decompressed distal small bowel suggestive of gastric outlet obstruction (arrow) (B) Ga-68 DOTATOC PET/CT scan showing somatostatin receptor positive peripancreatic nodules consistent with metastatic neuroendocrine tumor (chevron).

S2046 High-Grade Mucinous Adenocarcinoma of the Appendix With Signet Features and Omental Metastasis

Introduction: Primary adenocarcinoma of the appendix is an uncommon malignancy of the gastrointestinal tract. It was first described in 1882 and constitutes around 0.12 to 2.6 cases per one million people per year. In addition, signet-ring cell carcinoma of the appendix is extremely rare, it constitutes approximately 4% of all primary appendiceal neoplasms. There are few reported cases of primary signet cell appendiceal carcinoma. In this present report, we describe a rare case of primary signet ring cell carcinoma of the appendix with omental metastases in an 81-year-old male who underwent laparoscopic appendectomy. Case Description/Methods: We present a case of an 81-year-old male who had prior negative esophagogastroduodenoscopy (EGD) and colonoscopy in 2017 who presented to an urgent care in January 2021 with abdominal pain. Lab work was unremarkable, and the patient was sent home with instructions to visit the emergency department (ED) if he experienced fever, increased abdominal pain, or blood in the stool. Patient presented to the emergency department with increased abdominal pain in April 2021, and Computed Tomography (CT) scan of abdomen and pelvis with intravenous contrast showed a cystic appendiceal lesion with right peritoneal nodularity suspicious for peritoneal carcinomatosis. Therefore, the patient underwent appendectomy the following day revealing poorly differentiated, high-grade appendiceal adenocarcinoma with signet ring features, pT4a disease. Patient had a diagnostic laparoscopy in June 2021 and was found to have diffuse peritoneal carcinomatosis. Multiple biopsies were obtained and came back positive with high-grade mucinous adenocarcinoma with signet ring features. Patient agreed to pursue systemic chemotherapy. He was initiated on Capecitabine (Xeloda) 2000 mg tab PO, twice daily for 14 days and off for 7 days. Bevacizumab (Avastin) 7.5 mg IV infusion every 3 weeks (Figure). Discussion: Patients with appendiceal neoplasms may have vague lower abdominal pain but are usually asymptomatic with incidental diagnosis on imaging or appendectomy. Signet ring adenocarcinoma of the appendix typically secretes mucin leading to metastasis throughout the peritoneum and eventual obstruction. Treatment is based on stage and histology. Surgical resection and peritoneal debulking is possible. High-grade tumors require further prospective trials to evaluate treatment, but treatment options include surgical management, HIPEC, and systemic chemotherapy.Figure 1.: Histologic examination showing a signet cell carcinoma of the appendix infiltrating the peritoneum and diaphragm. (A) right lower quadrant peritoneum biopsy, (H&E stain 100x): High grade mucinous carcinoma peritonei with signet ring cells. Pool of mucin with a cluster of epithelium that shows signs of metastatic carcinoma (enlarged nuclei, atypia, pleomorphic changes). (B, C, and D) Right diaphragm peritoneum biopsy. High grade mucinous carcinoma peritonei with signet ring cells. Image B at 100x, C at 200x, and D at 400x. (E & F) immunohistochemical cytokeratin stain (AE1/AE3) shows strong positivity of high grade carcinoma. E at 100x, and F at 400x.

S280 Appropriateness of Scheduled 5-Year Colorectal Cancer Surveillance Colonoscopies at an Academic Medical Center

Introduction: Prudent adenoma detection and family history assessment results in increased surveillance colonoscopies for colorectal cancer screening (CRC), where recommended intervals for follow-up colonoscopies are based on prior colonoscopy findings (i.e., polyp number, size, pathology) as well as family history. Previous studies based on retrospective electronic health data determined that surveillance colonoscopies are often performed earlier than recommended intervals based on guidelines. These procedures expose patients to procedural risks, inconvenience with scheduling and unnecessary preps, and add to healthcare costs, as well as increase caseload for endoscopy centers that often have limited capacity. In the context of updated surveillance guidelines that lengthen follow-up intervals for some adenomas, we sought to assess the proportion of 5-year surveillance colonoscopies scheduled without appropriate indication. Methods: We conducted a retrospective cohort study of all outpatient endoscopic procedures scheduled in a tertiary, academic medical center over a 4-week period (4/25/22-5/20/22). We screened for cases that had an active Electronic Health Record (EHR) flag for 5-year screening colonoscopy and were classified by the ordering provider as having a screening, non-diagnostic indication, and then confirmed the EHR flag and indication with chart review. Two physicians conducted chart review of last colonoscopy and ordering provider documentation to evaluate indication and appropriateness for 5-year screening based on US Multi-Society Task Force February 2020 guidelines. Results: The 4-week period included 2,222 total procedures scheduled, of which 149 were colonoscopies scheduled for 5-year surveillance. Of these, 57% (85/149) were inappropriate based on current guidelines, which accounts for 4% (85/2,222) of total cases. 74% (63/85) of inappropriate cases were due to not meeting polyp-based guidelines, where 65% (55/85) was due to the 2020 change in guidelines. 24% (20/85) were based on inappropriately applied family history. (Figure) Conclusion: A majority of cases scheduled for 5-year surveillance were not indicated, where most were inappropriate based on updated polyp-based guidelines. Interventions targeting these cases and assessing overall appropriateness of cases may reduce patient harm and increase the capacity for necessary procedures.Figure 1.: (a) Appropriateness of Scheduled 5-Year Surveillance Colonoscopies (b) Reasons for Inappropriate Colonoscopy Scheduling

S196 Clostridioides difficile Infection (CDI) Increased in Individuals Diagnosed With Prior Colorectal Adenomas

Introduction: Clostridioides difficile infection (CDI) is increased in patients with colorectal cancer, but no one has investigated if CDI is also higher in individuals with prior history of colorectal adenomas seen on colonoscopy. Methods: We conducted a hospital-based cohort study composed of patients with diarrhea admitted to University of Michigan from 3/2016 to 12/2017 who were tested for C. difficile. Two hundred ninety-six diagnosed with C. difficile and 571 with non-C. difficile diarrhea were enrolled into the larger study. We abstracted prior colonoscopy reports and pathology reports from the medical records. Patients who had undergone colonoscopy were included in this analysis. Six hundred forty-seven underwent colonoscopy and 111 were diagnosed with colorectal adenomas prior to enrollment in the study. Logistic regression models were used to derive odds ratios (ORs) and 95% confidence intervals (95% CI) to evaluate comparisons between cases diagnosed with C. difficile and non-C. difficile diarrhea controls. We analyzed the association between history of colorectal adenoma diagnosis and CDI. (Figure, Table) Results: We found an increased risk of CDI in individuals with a prior colorectal adenoma (HR 1.64; 95% confidence interval (CI) 1.06-2.54) after adjusting for age, sex, obesity, complicated and uncomplicated diabetes and inflammatory bowel disease. Notably we also found a significant decreasing association between time since polypectomy and CDI with greater risk associated with greater time since colonoscopy. Conclusion: This study showed a higher incidence of CDI in individuals with a prior history of adenoma.Risk decreases over time since last polypectomy, which lends support to the hypothesis that there is a link between adenomas and subsequent CDI risk. Futures studies are needed to confirm this finding and elucidate mechanisms as this relationship could help target prophylactic measures in these individuals to avoid future infection.Figure 1.: Risk factors of CDI estimated with multivariate logistic regression. Model was adjusted for Complicated DM, Obesity, gender, history of adenoma, and age Table 1. - Baseline characteristics of subjects by Clostridioides difficile infection (CDI) diagnosis 1. Clostridioides difficile infection (CDI), Diabetes mellitus (DM) 2. Pearson's Chi-squared test; Fisher's exact test. 3. Interquartile range (IQR). 4. n (%) Characteristic Non-CDI1 Diarrhea (N=422) CDI1 Diarrhea (N=225) p-value2 Age 53 (39, 64)3 55 (45, 69)3 0.6 Non-Hispanic Caucasian 337 (80%)4 178 (79%)4 0.8 History of adenoma 58 (14%)4 53 (24%)4 0.002 Gender 0.11 Female 249 (59%)4 118 (52%)4 Male 73 (41%)4 107 (48%)4 Obesity 43 (10%)4 34 (15%)4 0.07 IBD 155 (37%)4 57 (25%)4 0.003 Complicated DM1 42 (10.0%)4 48 (21%)4 < 0.001

S2658 Symptomatic Sclerosing Mesenteritis: A Flank Problem

Introduction: Sclerosing mesenteritis is a rare diagnosis consisting of fatty inflammation and necrosis of the abdominal mesentery. Patients usually present asymptomatically or with vague, generalized systemic symptoms including abdominal pain, fever, and weight loss. Here, we present a case of a 72-year-old female with an unusual presentation of right flank pain in the diagnosis of sclerosing mesenteritis. Case Description/Methods: A 72 YO female was evaluated in the hospital for acute onset, intermittent right flank pain described as a spasm sensation. Her history was significant for multiple abdominopelvic surgeries, dating back almost 50 years and including appendectomy, herniorrhaphy, pelvic reconstruction and hysterectomy, and bladder sling placement. Her most recent surgery was the appendectomy 5 months prior to admission. There was no temporal or positional association of the pain. She had no associated fevers, malaise, changes in bowel habits, nausea, vomiting, melena, or hematochezia. Prior colonoscopy history was unknown. Physical exam showed a diffusely soft, n abdomen without any masses or organomegaly. Laboratory evaluation demonstrated leukocytosis and elevated ESR and CRP. The remaining laboratory work-up was within normal limits. CT abdomen and pelvis without contrast showed hazy attenuation of the mesenteric root with hypodense halos surrounding the mesenteric lymph nodes, suggestive of sclerosing mesenteritis. Surgical intervention was deferred given the patient's comorbid conditions. Given her presentation of flank pain, retroperitoneal ultrasonography was done which was negative for any acute pathologies. Discussion: The diagnosis of sclerosing mesenteritis is often an incidental finding on abdominal imaging, as seen in our patient case. Usually, such imaging studies are performed for evaluation of an abdominal mass seen in up to 35-50% of patients, however, in our case, it was performed for initial evaluation of her flank pain. In our patient case, the only risk factor for the development of sclerosing mesenteritis was her significant history of abdominal surgery. Studies have shown up to 30% of patients diagnosed with sclerosing mesenteritis have a history of prior abdominal surgery. A wide differential should be maintained in patients presenting without obvious abdominal complaints yet having a significant abdominal surgery history.

To scope or not - the challenges of managing patients with positive fecal occult blood test after recent colonoscopy.

BACKGROUNDColorectal cancer (CRC) is a major health problem. There is minimal consensus of the appropriate approach to manage patients with positive immunochemical fecal occult blood test (iFOBT), following a recent colonoscopy.AIMTo determine the prevalence of advanced neoplasia in patients with a positive iFOBT after a recent colonoscopy, and clinical and endoscopic predictors for advanced neoplasia.METHODSThe study recruited iFOBT positive patients who underwent colonoscopy between July 2015 to March 2020. Data collected included demographics, clinical characteristics, previous and current colonoscopy findings. Primary outcome was the prevalence of CRC and advanced neoplasia in a patient with positive iFOBT and previous colonoscopy. Secondary outcomes included identifying any clinical and endoscopic predictors for advanced neoplasia.RESULTSThe study included 1051 patients (male 53.6%; median age 63). Forty-two (4.0%) patients were diagnosed with CRC, 513 (48.8%) with adenoma/sessile serrated lesion (A-SSL) and 257 (24.5%) with advanced A-SSL (AA-SSL). A previous colonoscopy had been performed in 319 (30.3%). In this cohort, four (1.3%) were diagnosed with CRC, 146 (45.8%) with A-SSL and 56 (17.6%) with AA-SSL. Among those who had a colonoscopy within 4 years, none had CRC and 7 had AA-SSL. Of the 732 patients with no prior colonoscopy, there were 38 CRCs (5.2%). Independent predictors for advanced neoplasia were male [odds ratio (OR) = 1.80; 95% confidence interval (CI): 1.35-2.40; P < 0.001), age (OR = 1.04; 95%CI: 1.02-1.06; P < 0.001) and no previous colonoscopy (OR = 2.07; 95%CI: 1.49-2.87; P < 0.001).CONCLUSIONA previous colonoscopy, irrespective of its result, was associated with low prevalence of advanced neoplasia, and if performed within four years of a positive iFOBT result, was protective against CRC.

Promoting Informed Decisions About Colorectal Cancer Screening in Older Adults (PRIMED Study): a Physician Cluster Randomized Trial

BackgroundFor adults aged 76–85, guidelines recommend individualizing decision-making about whether to continue colorectal cancer (CRC) testing. These conversations can be challenging as they need to consider a patient’s CRC risk, life expectancy, and preferences.ObjectiveTo promote shared decision-making (SDM) for CRC testing decisions for older adults.DesignTwo-arm, multi-site cluster randomized trial, assigning physicians to Intervention and Comparator arms. Patients were surveyed shortly after the visit to assess outcomes. Analyses were intention-to-treat.Participants and SettingPrimary care physicians affiliated with 5 academic and community hospital networks and their patients aged 76–85 who were due for CRC testing and had a visit during the study period.InterventionsIntervention arm physicians completed a 2-h online course in SDM communication skills and received an electronic reminder of patients eligible for CRC testing shortly before the visit. Comparator arm received reminders only.Main MeasuresThe primary outcome was patient-reported SDM Process score (range 0–4 with higher scores indicating more SDM); secondary outcomes included patient-reported discussion of CRC screening, knowledge, intention, and satisfaction with the visit.Key ResultsSixty-seven physicians (Intervention n=34 and Comparator n=33) enrolled. Patient participants (n=466) were on average 79 years old, 50% with excellent or very good self-rated overall health, and 66% had one or more prior colonoscopies. Patients in the Intervention arm had higher SDM Process scores (adjusted mean difference 0.36 (95%CI (0.08, 0.64), p=0.01) than in the Comparator arm. More patients in the Intervention arm reported discussing CRC screening during the visit (72% vs. 60%, p=0.03) and had higher intention to follow through with their preferred approach (58.0% vs. 47.1, p=0.03). Knowledge scores and visit satisfaction did not differ significantly between arms.ConclusionPhysician training plus reminders were effective in increasing SDM and frequency of CRC testing discussions in an age group where SDM is essential.Trial RegistrationThe trial is registered on clinicaltrials.gov (NCT03959696).

Incidental Finding During Colonoscopy

Question: A 36-year-old man with a past medical history significant for type 2 diabetes mellitus and hyperlipidemia presented to the outpatient gastroenterology clinic due to unintentional 30-pound weight loss and diarrhea for the past year. He noted that his symptoms had been progressive over the last several months occurring on a daily basis. His diabetes had been under tight control with insulin, semaglutide, and metformin. Routine blood work including a complete metabolic panel, complete blood count, and thyroid studies were all within the normal limits. He had a remote history of a prior abnormal colonoscopy, however, a full report was unavailable and he reportedly failed to return for appropriate follow-up. Due to his symptoms, the patient was set up for a repeat colonoscopy. During colonoscopy, several large submucosal polypoid lesions were seen from the hepatic flexure to the proximal ascending colon. Several of the larger lesions were removed with snare to obtain adequate tissue. The endoscopic images can be seen in Figures A, B, and C. Pathology is shown in Figure D. What is the diagnosis? See the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Pneumatosis Cystoides Intestinalis is a rare disease characterized by gas-filled cysts in the submucosa and/or subserosa tissue. These lesions can be found anywhere in the gastrointestinal tract. Clinical presentation varies, with many patients being asymptomatic. Others may experience diarrhea, constipation, weight loss, and abdominal distention. The pathogenesis is also not clear regarding the disease. Most are thought to be idiopathic, however, there have been some iatrogenic causes that have been linked. These include postsurgical complications, certain medications, diabetes, emphysema, and autoimmune diseases (most notably systemic sclerosis) as some of the potential culprits.1Wang Y.J. Wang Y.M. Zheng Y.M. et al.Pneumatosis cystoides intestinalis: six case reports and a review of the literature.BMC Gastroenterol. 2018; 18: 100Crossref PubMed Scopus (35) Google Scholar Abdominal X-ray and computed tomography abdomen have a utility in establishing the gas pattern in intestines, but endoscopy with ultrasound and/or colonoscopy with biopsy confirms the diagnosis. Treatment for symptomatic patients includes hyperbaric oxygen, antibiotics with probiotics, endoscopic resection, or removal of the offending agent causing the disease.2Azzaroli F. Turco L. Ceroni L. et al.Pneumatosis cystoides intestinalis.World J Gastroenterol. 2011; 17: 4932-4936Crossref PubMed Scopus (51) Google Scholar As for the patient, his symptoms resolved with discontinuation of his semaglutide. He did not require any further treatment for the incidental finding of Pneumatosis Cystoides Intestinalis in his colon.

Clinicopathologic features of undetected dysplasia found in total colectomy or proctocolectomy specimens of patients with inflammatory bowel disease.

It remains controversial as to whether targeted biopsies should completely replace random biopsies for dysplasia surveillance in patients with inflammatory bowel disease (IBD). Several histologic patterns of nonconventional dysplasia have been described in IBD. This study aimed to investigate the rate and clinicopathologic features of dysplastic lesions found in total colectomy or proctocolectomy specimens that were undetected on prior colonoscopy. The study analyzed 207 consecutive IBD patients who underwent a total colectomy or proctocolectomy and had at least one high-definition colonoscopy prior to colectomy. Dysplasia found in the colectomy specimens was classified as undetected, only when there was no corresponding site of dysplasia detected on previous colonoscopic biopsies. Twenty-seven (13%) patients had 49 undetected dysplastic lesions found only at colectomy, while 22 (11%) had 31 previously detected dysplastic lesions only. The remaining 158 (76%) patients had no dysplasia. A greater proportion of the undetected (19%) or previously detected (23%) dysplasia group had concurrent primary sclerosing cholangitis compared with only 3% in the group without dysplasia (P < 0.001). The undetected dysplastic lesions were more likely to have nonconventional dysplastic features (76%), low-grade dysplasia (94%), and a flat/invisible gross appearance (73%) compared with the previously detected dysplastic lesions (13%, 68%, and 48%, respectively) (P < 0.05). Almost all patients with undetected dysplasia (93%) had a colonoscopy within 1 year of colectomy. The rate of undetected dysplasia is not insignificant (13%), suggesting that increased random biopsies may improve the rate of dysplasia detection, including nonconventional dysplasia.

An Unexpected Finding on Screening Colonoscopy in a Patient With Chronic Myelogenous Leukemia

Question: A 64-year-old woman presented for screening colonoscopy. Her only medical history included chronic myelogenous leukemia (CML) diagnosed 1 year prior that was improving and in the chronic phase with dasatinib 50 mg/d. She denied taking any other medications. The patient denied having any prior colonoscopies or any family history of colorectal cancer. She also denied any melena or hematochezia. She did report weight loss, which she attributed to her CML. On colonoscopy, multiple small polyps were seen throughout the colon ranging from 3 to 6 mm that were too numerous to count (Figure A). The polyps were friable and seemed to have mucous caps. A few of these polyps were removed from the transverse and sigmoid colon for pathological analysis (Figure B and C). What is the diagnosis? Look on page 58 for the answer and see the Gastroenterology web site (www.gastrojournal.org) for more information on submitting your favorite image to Clinical Challenges and Images in GI. Inflammatory reactive polyposis caused by dasatinib is a rare phenomenon and has only been described once in the Japanese literature.1Kobayashi M. Ikezawa K. Yamaura M. et al.[Inflammatory reactive polyposis caused by dasatinib: a case report].Nihon Shokakibyo Gakkai Zasshi. 2018; 115 ([In Japanese]): 977-984PubMed Google Scholar Our patient had polyps with mucoid discharge similar in appearance to those described in the Japanese paper. It was determined that the patient’s polyposis was caused by inflammation that was triggered by dasatinib. Four months after discontinuing dasatinib in the Japanese patient, a repeat colonoscopy revealed significant improvement in the polypoid lesions. In the case of our patient, we did not advise discontinuing dasatinib because she was on a low dose and did not tolerate other therapies for CML. The patient remained asymptomatic on follow-up. To our knowledge, this is the first case of dasatinib-induced inflammatory polyposis described in the English literature. Cases of hemorrhagic colitis secondary to dasatinib already exist. With dasatinib becoming a widely used therapy for Imatinib resistant CML, it is prudent to monitor for complications. Dasatinib is taken orally, making the gastrointestinal tract particularly vulnerable to complications. It is important to be aware of the inflammatory effects of dasatinib and this warrants further laboratory and clinical studies.2Nakamura S. Kino I. Akagi T. Inflammatory myoglandular polyps of the colon and rectum. A clinicopathological study of 32 pedunculated polyps, distinct from other types of polyps.Am J Surg Pathol. 1992; 16: 772-779Crossref PubMed Scopus (63) Google Scholar It is unknown if prolonged polyposis owing to dasatinib is a benign process or may eventually result in malignancy3Fei F. Yu Y. Schmitt A. et al.Dasatinib inhibits the proliferation and function of CD4+CD25+ regulatory T cells.Br J Haematol. 2009; 144: 195-205Crossref PubMed Scopus (60) Google Scholar The mechanism of polyposis has also not yet been elucidated and it is necessary to accumulate more cases to further our understanding. Therefore, it is important to offer screening colonoscopies to these patients at regular intervals.

DOP15 Fluorescent labelled vedolizumab for real-time visualization and quantification of local drug distribution and pharmacodynamics in Inflammatory Bowel Diseases during endoscopy

Abstract Background Vedolizumab is a monoclonal antibody which blocks integrin α4β7 inhibiting trafficking of T-lymphocytes into the gut. Unfortunately, up to 60% of vedolizumab patients experience non-response. The mechanism of action of vedolizumab is not elucidated, predictors of response are unknown and data for local drug distribution in the gut are lacking. In this clinical trial, we investigated the feasibility of assessing local distribution of fluorescently labelled vedolizumab in the gut mucosa of inflammatory bowel diseases (IBD) patients to finally enable prediction of therapy response in individual patients. Methods Vedolizumab (Entyvio, Takeda Pharma) was labelled to IRDye 800CW under cGMP conditions to yield clinical grade vedolizumab-800CW. In this dose-escalation trial, vedolizumab naïve IBD patients and IBD patients treated with vedolizumab for at least 14 weeks were included. Patients received an intravenous dose of fluorescently labelled vedolizumab of either 0 mg, 4.5 mg, 15 mg or 15 mg + 75 mg unlabelled vedolizumab 3 days prior colonoscopy. In vivo fluorescence imaging was assessed by fibre-based wide-field fluorescence molecular endoscopy (FME) and quantified by spectroscopy in healthy, mildly inflamed and severely inflamed tissue. All assessed tissue was biopsied for ex vivo examination of the fluorescent signal, fluorescence microscopy and spectroscopy. Results Up to submission 34 patients completed tracer injection and FME. An interim analysis was performed after 20 patients (5 in each dose group), which showed in severely inflamed tissue an 8 fold higher fluorescent signal in the 15 mg dose group (0.049 Q*μfa,x [mm-1]) compared to the control group (0.006 μfa,x [mm-1]) (p&amp;lt;0.05). Furthermore, the fluorescent signal within the 15 mg dose group was also 2.5 fold higher compared to healthy tissue (0.019 Q*μfa,x [mm-1]) (p&amp;lt;0.05).The addition of unlabelled vedolizumab gave similar results to the 15 mg group (p&amp;gt;0.99), suggesting that the drug target was still not saturated. The optimal dosage group of 15 mg was expanded up to 18 IBD patients, amongst them 6 IBD patients after 14 weeks of treatment regimen. Fluorescence microscopy showed clustering of fluorescent signals especially in inflamed mucosa. Additional experiments to detect vedolizumab target cells are ongoing. Conclusion In vivo visualization of fluorescent vedolizumab revealed a clear dose-dependent correlation between mucosal drug concentrations and the severity of mucosal inflammation. Fluorescence molecular endoscopy is a promising novel tool to get insight in drug distribution in IBD, detect target cells, assess target engagement and possibly predict therapy response in individual patients.