Duodenal pathology in patients with rumination syndrome: duodenal eosinophilia and increased intraepithelial lymphocytes

Background: Rumination syndrome is a functional gastrointestinal disorder characterized by effortless, postprandial regurgitation. Duodenal eosinophilia has been described in patients with functional dyspepsia. Because of the significant symptomatic overlap between functional dyspepsia and rumination syndrome, we hypothesized that histological changes might exist among patients with rumination syndrome. Methods: We included patients with rumination syndrome in whom we had obtained duodenal biopsies and compared these with controls. Digital images of biopsy specimens were analyzed for routine pathology and eosinophil counts by a pathologist blinded to the case–control status. Results: The 22 patients with rumination syndrome had a mean age of 39.2 years (range 21–71) and 77% were female. The 10 controls had a mean age of 34.3 (range 27–69) and 80% were female. There was a significant increase in the mean eosinophil count among the patients with rumination syndrome compared to controls, 26 per mm ² (range 16–42) versus 18 per mm ² (range 10–28), p = 0.006. Intraepithelial lymphocyte counts were significantly higher in rumination patients (mean 15/100 enterocytes, range 8–29) versus controls (mean 11/100 enterocytes, range 11–18), p = 0.02. Conclusion: Patients with rumination syndrome have subtle duodenal pathology with eosinophilia and increased intraepithelial lymphocyte counts compared to controls.