Figure 4.

Myxoid stroma and keloid-like hyalinized collagen bundles as two elemental components to categorize DR pattern. The DR pattern is categorized as immature, intermediate, or mature, based on two site-specific histological products of fibroblasts—myxoid stroma and hyalinized keloid-like collagens—that appear exclusively at the desmoplastic front. (A) Myxoid stroma: a fibrotic stroma with an amorphous mucinous stromal substance composed of a basophilic or amphophilic extracellular material. (B) Keloid-like collagen bundles are thick, hyalinized bundles of hypocellular collagen with bright eosinophilic hyalinization (arrow) (A, B: Original magnification, ×40 objective; H&E staining).