Gastric Lipohyperplasia Presenting As Gastric Polyposis: the First Case Report and Morphometric Study of Additional 127 Bariatric Specimens with a Proposal for Diagnostic Criteria

Introduction Excessive fat accumulation in the gastrointestinal tract is pathologic. Gastric mucosal polyposis due to excessive submucosal fat infiltration in a bariatric partial gastrectomy specimen was encountered, which has not been described in the literature. This observation prompted us to assess the extent of fat in gastric submucosa and study the incidence of mucosal polyposis due to submucosal fat accumulation in morbidly obese patients. Materials and Methods Archived pathology slides of 128 bariatric partial gastrectomy specimens including the index case and 89 control cases obtained from Whipple's procedure were examined. The amount of submucosal fat was categorized as 0 (no fat), 1 (up to 70% fat), and 2 (> 70% fat). The maximum submucosal fat thickness was measured with the interval cutoff of 5 mm and 10 mm. Results Of the 128 cases, 90 (70.3%) were category 1 and 31 (24.2%) were category 2. Maximum submucosal fat thickness was > 10 mm in 3 (2.3%) cases including the index case. The extent of submucosal fat accumulation correlated with the body mass index. The frequencies of category 2 and > 10 mm of fat thickness were higher in the bariatric patient group compared with the control group. Conclusion We propose a submucosal fat thickness of > 10 mm and diffuse (> 70%) fat accumulation as diagnostic criteria for gastric lipohyperplasia. Using these criteria, the prevalence of gastric lipohyperplasia in the morbidly obese population is 2.3%. A subset of these may present as gastric mucosal polyps.