Fluid levels in aneurysmal bone cysts.

Aneurysmal bone cysts are benign, expansile, osteolytic lesions of the bone. All the aneurysmal bone cysts studied in this case report were observed during the 2 year period, 1989 to 1991. The patients involved had received radiographic examination: plain and magnetic resonance (MR) image; one of the patients also received a computed tomography (CT). The plain radiograph generally showed a well-defined, expansile, osteolytic lesion associated with a pathologic fracture; the CT and MR images showed a fluid-fluid level within the lesion. This paper will report the findings of fluid-fluid levels, using radiographic images, in aneurysmal bone cysts.