Lumen-Apposing Metal Stent for Malignant Colon Obstruction

Introduction: Lumen-apposing metal stent (LAMS) is typically used to drain pancreatic fluid collections, but its distinct design has allowed for further procedures including managing benign gastrointestinal strictures. Malignant colon strictures are typically relieved by uncovered metal stents which are not removable and limited by stricture location. At the time of this report, there are no published cases of LAMS being used for malignant colon obstruction. We share a successful off-label use of LAMS in a patient with a short malignant colon obstruction preventing an emergent laparoscopy with diverting colostomy, allowing for removal of the LAMS once definitive treatment was planned. Case Description/Methods: A 64-year-old woman presented with progressive abdominal pain, distention, constipation and unintentional 10 lb weight loss over a month. Basic labs were unremarkable. Imaging revealed a large stricturing circumferential sigmoid mass (Figure 1A). The patient underwent a flexible sigmoidoscopy (flex sig) showing a malignant-appearing mass with severe stenosis measuring 10 mm in length (Figure 1B). A fiber scope was used to traverse the stricture and collect biopsies, revealing tubulovillous adenoma with high-grade dysplasia. Given high suspicion for malignancy, repeat flex sig was requested to obtain more biopsies. However, patient had worsening abdominal pain and was planned for emergent laparoscopy with diverting colostomy. After discussion with interventional gastroenterology, the decision was made to instead repeat flex sig and place LAMS across the stricture given the short stricture length, proximity to the rectum and no definitive diagnosis on pathology. LAMS placement resulted in abatement of obstipation and pain (Figure 1C). Biopsies confirmed invasive adenocarcinoma of rectum necessitating elective robotic low anterior resection. Flex sig with removal of LAMS was performed 24 hours prior to surgery. The patient tolerated the procedure and surgery well and continues to follow with oncology. Discussion: There are many studies showing efficacy using other stents, such as self-expanding metal stents, to minimize emergent surgical resection and ostomies for malignant colon obstruction; however, they cannot be removed and are limited by location. We present a unique case in which LAMS was used for a malignant colon obstruction significantly reducing risk by preventing emergent surgery, allowing for removal of the stent prior to definitive surgery and improving quality of life by preventing ostomy.Figure 1.: A. Magnetic resonance imaging of rectal mass measuring 4.2 x 2.6 x 2.7cm B. Flexible sigmoidoscopy demonstrating a malignant appearing severe intrinsic stenosis approximately 13 cm proximal to anal verge C. Flexible sigmoidoscopy with successful placement of 15 x 15 mm LAMS through colonic obstruction.