Clinicopathologic features of misplaced glands in colonic polyps: Morphologic spectrum and association with dysplasia

Misplaced glands in colonic polyps are important to identify and to differe ntiate from invasive adenocarcinomas. Certain microscopic features are cons idered helpful to make this distinction. We have examined 650 polyps and fo und 23 (3%) with misplaced glands. A significant number (17 of 23 cases) la cked the typical previously described microscopic features of misplaced gla nds. Two distinct growth patterns of the misplaced glands were identified i n our series: an infiltrative and a pushing pattern, both lacking stromal d esmoplasia. Only six of the 23 polyps showed the previously described assoc iated changes such as hemorrhage and mucin pools. In addition, five of the polyps had high-grade dysplasia in the misplaced glands, four of which show ed the infiltrative pattern of growth. Two cases were associated with a syn chronous adenocarcinoma of the colon. The recognition of these two patterns of misplaced glands with or without stromal changes, and the association w ith high-grade dysplasia should be considered in the differential diagnosis between misplaced glands and adenocarcinoma.