Solid variant of an aneurysmal bone cyst (giant cell reparative granuloma) of the 3rd lumbar vertebra.

A 9-year-old girl with a solid variant of an aneurysmal bone cyst in the 3rd lumbar vertebra showed a good response to low-dose radiation as the only treatment. The solid variant of aneurysmal bone cyst is thought to be a reactive response to intraosseous hemorrhage and is also called giant cell reparative granuloma or giant cell reaction. These lesions in the jaw and the short tubular bones of the hands and feet frequently recur after surgery. Aneurysmal bone cysts of the spine also show a fairly high recurrence rate after incomplete resection or radiation therapy. However, 7 previous cases of the solid variant of aneurysmal bone cyst in the spine and this case did not show recurrence after a mean follow-up period of 45 months. This difference in behaviour suggests that the solid variant should be recognized before surgery as being distinct from conventional aneurysmal bone cysts, especially in the spine.