A Novel Chronic Enteropathy Associated with SLCO2A1 Gene Mutation: Enterography Findings in a Multicenter Korean Registry

Abstract

Objective: Chronic enteropathy associated with SLCO2A1 gene (CEAS) is a recently recognized disease. We aimed to evaluate the enterographic findings of CEAS.

Materials and methods: Altogether, 14 patients with CEAS were confirmed based on known SLCO2A1 mutations. They were registered in a multicenter Korean registry between July 2018 and July 2021. Nine of the patients (37.2 ± 13 years; all female) who underwent surgery-naïve-state computed tomography enterography (CTE) or magnetic resonance enterography (MRE) were identified. Two experienced radiologists reviewed 25 and 2 sets of CTE and MRE examinations, respectively, regarding the small bowel findings.

Results: In initial evaluation, eight patients showed a total of 37 areas with mural abnormalities in the ileum on CTE, including 1-4 segments in six and > 10 segments in two patients. One patient showed unremarkable CTE. The involved segments were 10-85 mm (median, 20 mm) in length, 3-14 mm (median, 7 mm) in mural thickness, circumferential in 86.5% (32/37), and showed stratified enhancement in the enteric and portal phases in 91.9% (34/37) and 81.8% (9/11), respectively. Perienteric infiltration and prominent vasa recta were noted in 2.7% (1/37) and 13.5% (5/37), respectively. Bowel strictures were identified in six patients (66.7%), with a maximum upstream diameter of 31-48 mm. Two patients underwent surgery for strictures immediately after the initial enterography. Follow-up CTE and MRE in the remaining patients showed minimal-to-mild changes in the extent and thickness of the mural involvement for 17-138 months (median, 47.5 months) after initial enterography. Two patients required surgery for bowel stricture at 19 and 38 months of follow-up, respectively.

Conclusion: CEAS of the small bowel typically manifested on enterography in varying numbers and lengths of abnormal ileal segments that showed circumferential mural thickening with layered enhancement without perienteric abnormalities. The lesions caused bowel strictures that required surgery in some patients.

Keywords: Chronic enteropathy associated with SLCO2A1 gene; Chronic intestinal ulcer; Crohn's disease; Enterography; Inflammatory bowel disease; Radiology.

Fig. 1. A 52-year-old (at initial diagnosis) female with chronic enteropathy associated with SLCO2A1 gene (CEAS) who was initially evaluated with computed tomography enterography (CTE) and then followed with magnetic resonance enterography (MRE). CTE images (A, enteric phase; B, portal phase) show an ileal segment involved with CEAS (arrows) which demonstrates circumferential wall thickening with stratified enhancement in the distal ileum. On a follow-up MRE (C, enteric-phase contrast-enhanced T1; D, fat-saturated T2; E, diffusion-weighted imaging; F, apparent diffusion coefficient map) at 130 months from the CTE, the lesion (arrows) shows similar findings, except for a slight increase in mural thickness. The involved bowel wall shows a slightly increased signal on T2 and mild restricted diffusion.

Fig. 2. A 45-year-old (at initial diagnosis) female who underwent surgery for ileal stricture caused by chronic enteropathy associated with SLCO2A1 gene (CEAS). A, B: Computed tomography enterography (CTE) images in the enteric phase obtained at initial presentation (A and B) show ileal segments involved with CEAS (arrows), manifesting mostly as circumferential wall thickening with stratified enhancement. Stricture in the distal ileal segment (open arrow) caused dilatation of the upstream small bowel (arrowheads). The patient underwent surgery without delay after CTE due to the stricture. C, D: Microscopic examination of the surgical specimen reveals an active ulcer with trapezoid or radiating submucosal fibrosis (arrows in C) and mild chronic transmural inflammation and a healed ulcer (inactive ulcer scar) showing luminal web-like protruding submucosal fibrosis (arrows in D) (hematoxylin and eosin staining, × 12.5).