Aneurysmal bone cysts (ABC) are benign lesions that occur more frequently in the metaphyses of long bones, especially distal femur, the proximal tibia and vertebral posterior bodies. It can occur at any age but most patients are diagnosed in the first 2 decades of life. It can exist as primary bone lesion or as secondary lesions arising in association with other osseous conditions, namely giant cell tumor, chondroblastoma, chondromyxoid fibroma and fibrous dysplasia. Pain and swelling are the most common complaints.