1. A case of extradural spinal cyst associated with kyphosis dorsalis juvenilis is reported.
2. Sixteen other cases of spinal extradural cysts collected from the literature are presented.
3. The clinical picture of an adolescent with progressive paraplegia, together with erosion of the vertebral bodies in the mid-thoracic region as seen in kyphosis dorsalis juvenilis, is pathognomonic of an extradural spinal cyst.
4. All cases of kyphosis dorsalis juvenilis should be carefully examined for evidence of spinal-cord compression and for roentgenographic evidence of enlargement of the spinal canal.
5. The deformity seen in kyphosis dorsalis juvenilis with extradural cyst results from venous stasis secondary to the presence of the cyst.
6. The etiology of kyphosis dorsalis juvenilis unassociated with an extradural cyst is unknown.
7. Early surgical intervention with removal of the intraspinal cyst usually results in complete cure with relief of all signs of spinal-cord compression and prompt arrest of the kyphotic deformity.