Fig. 2

Representative pathological findings of OF in both patient II:2 and III:1. A The well-demarcated tumor showing hypercellularity component. B A partly encapsulated leision in which psammomatoid calcified spherules lying in hypercellular stroma. C A mineralization component of the lesion and a thin layer of fibrous tissue which separated from the surrounding normal bone. D Low power H&E image demonstrates interface between mineralized and non-mineralized tissue. E Cellular osteoid trabeculae formation lacking of typical osteoblastic rimming, mineralization often at the center of these trabeculae (medium-magnification photomicrograph of C). F A medium power view of D showing acellular basophilic cementum-like structures. The calcified tissue shows a distinctive “brush boarder” that interfaces with the surrounding stroma (arrows). G Hypocellular area with collagenized stroma cells. H Fibrous component with moderatecellular density, absence of calcifications completely (low-magnification image). I Dense fibrous cells are hyperchromatic and absence of mitosis. J Hypocellular area demonstrating loose edema-like stroma. Low-magnification (K) and high-magnification (L) photomicrographs showing a perivascular growth pattern (perivascular cells are relatively higher density than those of away from vessels)