Ganglion cyst of the odontoid process. Case report and review of the literature.

Study Design: This case report illustrates that although it is rare, a ganglion cyst can occur intraosseously in the odontoid process.

Objectives: The tissue diagnosis was established by surgical resection of the cyst membrane and evacuation of the cyst content. The patient tolerated the procedure well, and the hospital course was uneventful.

Summary Of Background Data: Synovial cyst of the spine is uncommon and is usually found in the lumbar region. Its occurrence in the cervical spine is rare, and no cases in the odontoid process, to the authors' knowledge, have been reported.

Methods: This patient was evaluated initially for neck pain, which led to radiographic studies depicting the lesion. It raised the suspicion of metastatic neoplastic process, although the search for primary source proved to be negative. A biopsy was indicated.

Results: Surgical findings consisted of mucoid material field cavity lined by a thin membrane. The cyst was excised, and pathologic evaluation confirmed the diagnosis of synovial cyst.

Conclusion: The correct radiographic diagnosis of this patient was not made because of lack of experience with such lesions in this location. The authors hope that this case report helps raise the awareness of clinicians in considering this diagnosis when facing similar radiographic presentation.