Intermittent atlantoaxial subluxation caused by a prolapsing neurofibroma. Case report.

In this report, the authors describe a unique case of intermittent high cervical cord compression caused by a prolapsing neurofibroma at the C1-2 level. This 21-year-old man with known neurofibromatosis Type 1 presented with a mass between the anterior arch of the atlas and the odontoid peg, causing atlantoaxial dissociation and cord compression. The cervicomedullary compression appeared to be caused in part by the neurofibroma but also by the abnormal alignment and thickening of the ligaments between the clivus and C-2. Preoperative imaging repeated on the morning of surgery revealed that the atlantoaxial dissociation had reduced with relief of cord compression and the lesion prolapsed inferiorly. The authors discuss this unusual lesion and describe the associated operative findings and surgical management.