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 differentiate from invasive adenocarcinomas. Certain microscopic features are considered helpful to make this distinction. We have examined 650 polyps and found 23 (3%) with misplaced glands. A significant number (17 of 23 cases) lacked the typical previously described microscopic features of misplaced glands. TWo distinct growth patterns of the misplaced glands were identified in our series: an infiltrative and a pushing pattern, both lacking stromal desmoplasia. Only six of the 23 polyps showed the previously described associated changes such as hemorrhage and mucin pools. In addition, five of the polyps had high-grade dysplasia in the misplaced glands, four of which showed the infiltrative pattern of growth. TWo cases were associated with a synchronous adenocarcinoma of the colon. The recognition of these two patterns of misplaced glands with or without stromal changes, and the association with high-grade dysplasia should be considered in the differential diagnosis between misplaced glands and adenocarcinoma.