[Cervical retro-odontoid pseudo-tumor treated with posterior decompression surgery].

A cervical retro-odontoid pseudo-tumor, which is considered as a reactive fibrocartilaginous mass, is a rare condition in cervical myelopathy. A 63-year-old male, with repeated neck axial movements by a long-term leisure-time cycling, developed subacute myelopathy. Cervical MRI showed a mass lesion at the retro-odontoid region, compressing to the upper spinal cord. After detailed systemic and local examinations that ruled out primary or metastatic malignancy and inflammatory disorders such as rheumatoid arthritis or chronic kidney diseases, a retro-odontoid pseudo-tumor was diagnosed clinically. The patient underwent posterior C1-laminectomy without tumor resection and its pathological confirmation. After the surgery, his neurological signs of cervical myelopathy improved, and a follow-up MRI one year later showed a mild reduction of the tumor size. The neuro-physicians should recognize the relatively benign pseudotumor in cervical myelopathy, because the tumor size usually shows no further enlargement or regression only after decompression surgery without tumor resection.