Basilar invagination associated with an intercarotid paraganglioma--case report.

A 24-year-old female presented with basilar invagination and kyphoscoliosis of the cervical spine associated with a large intercarotid paraganglioma. She had suffered from pharyngeal discomfort from the age of 9 years due to the tumor. The tumor had originated from the right carotid body and extended in the parapharyngeal space compressing the upper cervical spine. Presumably the slowly growing tumor had caused the kyphoscoliosis and disturbed osseous development of the occipito-atlanto-axial complex, resulting in anterior basilar invagination, hypoplasia of the clivus, and aplasia of the posterior arch of the atlas.