Image Description
Aneurysmal Bone Cyst (ABC) - Microscopic Features: The blood-filled cystic spaces are separated by fibrous septa composed of loosely arranged plump fibroblastic cells, multinucleated osteoclast-type giant cells, macrophages and other inflammatory cells. A few solid foci composed of fibroblastic proliferation are usually present. Mitotic activity is brisk; however, atypical forms are not seen. There is no cytologic atypia. Necrosis is uncommon in the absence of a pathologic fracture.