Figure 1.

Morphological aspects of GCTB. (A) GCTB is composed of four major components. These are large osteoclastic giant cells, macrophages, mononuclear spindle-shaped cells and the extracellular matrix. (B) Immunofluorescent membrane expression of CD33 (green) by osteoclasts (white arrows). Some macrophages express CD14 (red) on their membrane (asterix *). Note that other macrophages express CD14 as well CD33 on their membrane. (C) CD31 immunohistochemistry demonstrates the presence of many intratumoural blood vessels. Note that almost every large osteoclastic giant cell is connected to at least one blood vessel branch. (D) RANKL expression by the neoplastic mononuclear spindle-shaped cells in order to enhance osteoclastogenesis.