S6166 Rare Etiology of Small Bowel Obstruction in Crohn's Disease: A Case of Endosalpingiosis

Introduction: Small bowel obstruction (SBO) is a well-recognized complication of Crohn’s disease, with strictures accounting for up to 54% of cases. By contrast, endosalpingiosis (ES) is a rare and poorly understood condition defined as the presence of endothelial cells resembling fallopian tube epithelium found outside the fallopian tubes. Although usually considered a benign finding, emerging evidence points to its potential clinical significance, particularly concerning gynecologic malignancies and gastrointestinal involvement. We present an interesting case of SBO in a patient with Crohn’s disease caused by an ES-induced stricture, an association not previously reported in the literature. Case Description/Methods: A 69-year-old woman with a long-standing history of fistulizing Crohn’s disease on mesalamine presented with right lower quadrant pain. Computed tomography imaging revealed a high-grade distal SBO near the ileocecal valve. Due to worsening symptoms, the patient underwent exploratory laparotomy with ileocecal resection and right hemicolectomy. Histologic examination of the resected specimen revealed focal areas of mucosal ulceration with fissuring, consistent with Crohn’s disease. Yet, most of the resected bowel was without evidence of active Crohn’s disease. Interestingly, there were numerous glandular inclusions embedded within the muscularis propria, which were lined by a single layer of bland-appearing columnar and ciliated columnar epithelium, closely resembling that of the fallopian tube. Immunohistochemical staining was consistent with müllerian-derived epithelium, supporting ES as the underlying cause of the stricture. Discussion: Although ES is not inherently inflammatory, its presence within the gastrointestinal tract may lead to complications such as fibrosis and adhesion, especially in patients with other comorbidities such as Crohn's disease. In our case, histopathologic examination of the ileocecal stricture revealed intramural ES with only minimal evidence of active inflammatory bowel disease. This finding suggests that the SBO was primarily driven by ES-related fibrosis or mass effect rather than Crohn’s disease. To our knowledge, this is the first reported case of SBO due to ES in the context of Crohn’s disease, highlighting a previously unrecognized overlap between these 2 distinct conditions.