Klippel-Feil Syndrome in Association with a Craniocervical Arachnoid Cyst: A Unique Case Report

Introduction: Klippel-Feil syndrome, or Brevicollis, is a complex congenital disorder caused by the improper segmentation of the cervical vertebrae. We present a very rare case of a patient with Klippel-Feil syndrome who presented with an intradural arachnoid cyst at the craniocervical junction.

Clinical Presentation: A 46-year-old woman presented to our clinic in April 2010 with complaints of progressively worsening headaches and dizziness for 18 months. She also demonstrated mild upper extremity weakness bilaterally. MRI revealed fused cervical vertebrae and a dorsal intradural arachnoid cyst at the craniocervical junction, extending down to the second cervical level. Due to worsening symptoms, the patient was scheduled for surgery.

A midline skin incision extending from the superior aspect of the inion to the level of C4 was made, and subperiosteal dissection exposed the posterior suboccipital region and the upper cervical spine. A defect was found between the lower occipital bone and the fused upper cervical vertebrae. To minimize bony destabilization, the dura was opened through this defect without removing any bone from the upper spine or the lower occipital bone. On opening the dura, a large cystic fenestrated mass draining a clear fluid was encountered. The adhesions between the cyst, the lower brainstem, fourth ventricle, and vertebral artery were carefully excised under direct visualization by a 0-degree endoscope that was introduced through the defect. Partial excision of the cyst wall was performed. There were no complications intraoperatively, and the patient has remained symptom free for over a year postoperatively with good radiological decompression.

Conclusion: We report a unique association between a craniocervical arachnoid cyst and Klippel-Feil syndrome. To our knowledge, no other cases of this association have been reported in the literature. Arachnoid cysts should be part of the differentials in the presence of worsening myelopathic symptoms or pain in patients with Klippel-Feil syndrome.