Massive Gastric Juvenile Polyposis A Clinicopathologic Study Using SMAD4 Immunohistochemistry

Objectives: Juvenile polyps involving the stomach are uncommon. Massive gastric juvenile polyposis is even rarer. Methods: We describe the clinicopathologic features of nine cases of massive gastric juvenile polyposis. Results: All patients had anemia; four had hypoalbuminemia. The polyps were composed predominantly of dilated crypts lined by columnar epithelium and abundant edematous stroma with mixed inflammatory infiltrates. One patient had a poorly differentiated adenocarcinoma, arising in juvenile polyp-associated intraepithelial neoplasia. A second patient had a well-differentiated intramucosal adenocarcinoma arising in a juvenile polyp with high-grade dysplasia. Three of our cases had polyposis restricted to the stomach. Six (66.6%) had loss of SMAD4 immunoreactivity, making them subject to severe bleeding and hypoproteinemia, as well as developing severe dysplasia or adenocarcinoma. Conclusions: SMAD4 immunohistochemstry is a helpful ancillary diagnostic test in cases of suspected juvenile polyposis syndrome involving the stomach.