Aneurysmal bone cyst

Summary Authors report on the results of treatment of 52 primary and 16 secondary aneurysmal bone cysts (ABC). ABC grow rapidly; 84% of them have already destroyed more than the half of the bone width at recognition. En bloc resection is preferred when the ABC is growing superficially and eccentrically and more than half of the bone width is intact. Careful curettage and bone grafting still remains the surgical method of choice in the majority of cases, when the ABC is more destructive and affects the subchondral bone of the joints. Segmental resection is only indicated when removal of the affected bone does not influence the function of the extremity. Superselective embolization of the cyst was performed in seven cases with excellent results. This method is suggested for ABC in certain locations inaccessible to surgical intervention, e.g., the pelvis, or to avoid excessive bleeding in hypervascularized tumors. In one case, however, an incomplete rebuilding of the ABC could only be achieved by the administration of calcitonin. The 16 cases of secondary ABC were observed mostly in association with osteoblastomas, giant-cell tumors, and osteosarcomas. The incidence of the secondary ABC was 23% in the whole ABC group but not more than 2–4% among the osteosarcomas and giant-cell tumors. Secondary ABC may confuse the histological and clinical diagnoses and that, especially in cases of osteosarcoma, may have fatal consequences.