Vertebra plana of the lumbar spine caused by an aneurysmal bone cyst: a case report.

The patient was a 15-year-old girl who had a lesion of the fourth lumbar vertebra. Plain radiographs suggested vertebra plana, with complete collapse of the body of the fourth lumbar vertebra and no involvement of the intervertebral disk spaces. The presumptive diagnosis was eosinophilic granuloma. Progressive neurologic symptoms required surgical excision of the lesion, decompression, and fusion. Histopathologic examination of the operative specimen confirmed the diagnosis of an aneurysmal bone cyst.