Primary vertebral echinococcosis: four cases reports and review of literature.

Primary vertebral echinococcosis has been considered to be a hypothetical and exceptional possibility. It affects bones in 1% of reported cases. Spine is involved in 45-50% of these. The disease preferentially affects the thoracic spine. It begins as a single primary cyst containing daughter cysts. We report four cases of primary vertebral echinococcosis, extending into the extradural space without any other primary site of infection. We conclude that primary vertebral echinococcosis, although rare should be considered in destructive lesions of the vertebrae and spine in regions that the disease is endemic. Advanced imaging studies should be performed to diagnose the disease. Early decompressive surgery of the spine, with chemotherapy, is the treatment of choice for these patients.