Fig. 3

First surgical specimen. a Ossifying fibroma-like area: It is formed by the proliferation of mild spindle cells, accompanied by new bone trabeculae lined by osteoblasts. b Blue-purple smoky calcification can be seen around the remaining host bone. c The most actively proliferating spindle-shaped cell area. Some cells are slightly atypia showing no mitosis. (Haematoxylin and Eosin stained, original magnification × 100)