S3572 Chronic Abdominal Pain Mystery: Median Arcuate Ligament Syndrome

Abstract

Discussion: Adults with collagenous gastritis usually present with anemia, abdominal pain, and diarrhea. It is categorized by three different inflammatory environments, a lymphocytic gastritis-like pattern, an eosinophil-rich pattern, and an atrophic gastritis-like pattern. There are many proposed treatments for collagenous gastritis that have not been substantiated with clinical trial data. Observational data suggests that topical budesonide may be efficacious for collagenous gastritis. IV vedolizumab is a monoclonal antibody against a4b7 integrin and is commonly used in inflammatory bowel disease. One proposed mechanism of collagenous gastritis is band-like collagen deposition as a result of inflammation and mucosal injury however this does not consider the active inflammatory milieu found in certain cases. A more likely explanation involves an immune-mediated phenomenon related to epithelial injury and antibody production. Therefore, the efficacy of IV vedolizumab may be related to its ability to reduce the inflammatory response in the intestinal epithelium. Further investigation is necessary to assess the response to vedolizumab in other patients with collagenous gastritis.[3570] Figure 1. Histopathology of gastric body before and after treatment with IV vedolizumab. A, Initial histopathology prior to treatment showing subepithelial collagen deposition of .10 um with sloughing of surface epithelium, loss of specialized gastric glands, and an inflammatory infiltrate of eosinophils, plasma cells, and lymphocytes. B, Initial histopathology prior to treatment with Trichrome stain highlighting collagen deposition. C, Histopathology following treatment with IV vedolizumab showing healthy surface foveolar cells and specialized gastric glands with few plasma cells and no increase in subepithelial collagen. All photomicrographs obtained at 403 original magnification.