Sporadic Fundic Gland Polyps with Low-Grade Dysplasia: A Large Case Series To Assess Clinicopathologic Behavior
Mary Levy, Baishali Bhattacharya. Caris Diagnostics, Phoenix, AZ
Background: Fundic gland polyps (FGPs) occur in two different clinical settings, sporadic and syndromic (familial adenomatous polyposis, or FAP). Sporadic FGPs are benign epithelial polyps associated with chronic use of proton-pump inhibitors (PPIs). Epithelial dysplasia (low- or high-grade) is extremely rare in FGPs, and, therefore progression data from large series are lacking. The aim of this study was to evaluate the clinical, morphologic and immunohistochemical features in a large series of sporadic FGPs with epithelial dysplasia.
Design: From a total of 28,000 FGPs diagnosed in our institution between January 2008 to July 2011, we extracted all cases with a reported diagnosis of low-grade dysplasia (LGD); we then reviewed the slides and selected cases that met the following criteria: hyperchromasia, loss of mucin, nuclear enlargement, and pseudostratification, limited to the surface or foveolar epithelium. Selected cases were stained for p53, Ki-67, and B-catenin.
Results: There were 48 FGPs (0.17%) with histologically confirmed low-grade dysplasia (LGD) and none with high-grade dysplasia; 13 were associated with FAP (age range 14 to 64 years, mean 46 years; 3 men and 10 women), and 35 were sporadic (age range 21 to 78 years, mean 52.1 years; 23 women and 12 men, 2:1 ratio). The indication for endoscopy in the sporadic FGP with LGD included heartburn, follow up of Barrett's, and non response to PPI (all of our study patients were on PPI). None of the cases had Helicobacter pylori infection. 15 sporadic and 5 syndromic FGPs with LGD and 5 sporadic FGPs without dysplasia were selected for immunohistochemical staining with p53, Ki-67, and B-catenin. None of the cases showed overexpression of p53 protein. Ki-67 showed a high proliferation index in the stem cell neck region and surface epithelium in the sporadic and syndromic FGPs with LGD. The deeper glands within the polyps were completely negative. The sporadic FGP without dysplasia showed absent surface nuclear staining. Nuclear accumulation of B-catenin was observed in 4 out of 5 (80%) syndromic FGPs with LGD and 2 out of 15 (13.3%) sporadic FGPs with LGD.
Conclusions: To date, this is the largest study evaluating the clinicopathologic findings of sporadic FGPs with LGD. Sporadic FGPs with LGD were more often seen in females and were associated with PPI use. The sporadic FGP with LGD had lower B-catenin nuclear staining. We found that syndromic and sporadic FGPs with LGD did not differ with respect to proliferative activity and p53 expression.
Tuesday, March 20, 2012 11:15 AM
Platform Session: Section D, Tuesday Morning