Acquired butterfly vertebra as a sequela of eosinophilic granuloma.

Butterfly vertebras are an abnormal embryological formation of the spinal bodies that occur because of a lack of fusion of the chondrification centers of the vertebral bodies. Langerhans cell histiocytosis is an entity that frequently involves vertebral bodies resulting in flat vertebras, and recovery of the vertebral body height is a very unusual finding. We present a case report of a pediatric patient with a thoracic acquired butterfly vertebra which occurred secondary to a Langerhans cell histiocytosis involvement. It is extremely rare to find vertebra plana that regains its complete height but is even more infrequent to evidence of a butterfly vertebra deformity that is not congenital.