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Obliterative Muscularization of the Small Bowel Submucosa in Fibrostenotic Crohn's Disease

McNeill, Matthew B. MD1; Suarez, Yvelisse MD2; Axelrad, Jordan MD1

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doi: 10.14309/crj.0000000000000357
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A 33-year-old white woman with no significant medical history presented with multiple episodes of small bowel obstruction suggestive of Crohn's disease (CD). During all the episodes, inflammatory biomarkers, including C-reactive protein, erythrocyte sedimentation rate, and fecal calprotectin, and stool studies for pathogens by polymerase chain reaction were negative. After the first obstruction, upper and lower endoscopic evaluations did not demonstrate endoscopic or histologic evidence of inflammatory bowel disease. She improved with conservative management with steroids and bowel rest. After the second obstruction, magnetic resonance enterography demonstrated 5 cm of wall thickening, narrowing, and mural hyperenhancement approximately 3 cm proximal to the ileocecal valve. A retrograde double-balloon enteroscopy showed a very distal terminal ileal narrowing without mucosal ulceration or inflammation (Figure 1). A subsequent magnetic resonance enterography showed 7 cm of nodular wall thickening without hyperemia, restricted diffusion, or obstruction in the distal ileum.

Figure 1.
Figure 1.:
A retrograde double-balloon enteroscopy showing distal terminal ileal narrowing without mucosal ulceration or inflammation.

Given the multiple obstructions concerning for CD, she was referred for surgery. Ileocolic resection demonstrated an edematous terminal ileum with extraluminal creeping fat (Figure 2). There were no luminal mucosal ulcerations, strictures, or lesions on gross examination. Histopathology demonstrated focal mildly active ileitis and neural inflammation with fibrosis of the submucosa without transmural inflammation concerning for submucosal, extraluminal CD (Figure 3). Obliterative muscularization of the submucosa has been proposed as a possible mechanism of small bowel obstruction in CD (Figure 4). Postoperatively, the patient did well without endoscopic or radiographic evidence of CD. CD traditionally presents with transmural inflammation. Isolated submucosal, extraluminal inflammation leading to recurrent obstruction is a rare presentation.1 CD guidelines recommend surgical intervention for profound or recurrent fibrostenotic disease.2

Figure 2.
Figure 2.:
Ileocolic resection showing an edematous terminal ileum with extraluminal creeping fat.
Figure 3.
Figure 3.:
Histopathology of ileal specimen showing no transmural inflammation.
Figure 4.
Figure 4.:
Submucosa showing fibrosis and muscularization.


Author contributions: MB McNeill wrote the manuscript and is the article guarantor. Y. Suarez and J. Axelrad edited the manuscript.

Financial disclosure: None to report.

Informed consent was obtained for this case report.


1. Koukoulis G, Ke Y, Henley JD, Cummings OW. Obliterative muscularization of the small bowel submucosa in Crohn's disease. Arch Pathol Lab Med. 2001;125(10):1331–4.
2. Lichtenstein GR, Loftus EV, Isaacs KL, Regueiro MD, Gerson LB, Sands BE. ACG clinical guideline: Management of Crohn's disease in adults. Am J Gastroenterol. 2018;113(4):481–517.
© 2020 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.