Usually significant architectural and/or cytologic atypia
Usually lacks significant architectural and/or cytologic atypia (high grade dysplasia may be misplaced occasionally but is typically accompanied by bland adenoma tissue)
Desmoplastic stroma
Inflammatory or fibrotic stroma
Infiltrates through muscularis mucosae
Frequently demonstrable continuity with surface through a gap in the muscularis mucosae
Hemosiderin restricted to head of polyp
Hemosiderin common in stalk stroma
Glands not accompanied by lamina propria
Glands may be accompanied by lamina propria
Usually infiltrative, non-circumscribed
Frequently circumscribed
May occur throughout the colorectum
Virtually restricted to left colon
Collagen type IV weak, discontinuous
Collagen type IV strong, continuous around epithelial nests
E cadherin markedly decreased staining compared to overlying adenoma
E cadherin same intensity as overlying adenoma (high grade dysplasia may show decrease)
