Aneurysmal Bone Cysts and Giant Cell Tumors of the Spine

Tumors affecting the spinal column include primary and metastatic tumors. Primary tumors of the spine comprise less than 11% of all primary musculoskeletal tumors, and only 4.2% of all spine tumors and include aneurysmal bone cysts (ABCs) and giant cell tumors (GCTs). The radiographic and histologic features of these tumors may appear similar, as both create osteolysis and cystic patterns in the vertebra, and both may contain giant cells and hemosiderin on histology. However, the biological behavior and clinical course of these tumors differ significantly and an effective approach to treatment is distinct in these conditions. The purpose of this article is to describe ABCs as a primary benign tumor of the spine and to differentiate this entity from GCTs of the spine, which have the capacity to undergo osteosarcomatous transformation and metastasize.