Over a 7-month period, a 55-year-old female with a history of athetoid cerebral palsy developed a progressive quadriparesis. Cervical X-rays showed atlanto-axial subluxation (AAS) with instability. The cervical MR showed a retro-odontoid “pseudotumor” focally compressing the ventral cord, while the cervical CT showed OALL extending from C3-C6. For her progressive myelopathy and retro-odontoid mass with AAS, she underwent that a C0-C2 posterior fusion with C1 was arch resection. Postoperatively, although her quadriparesis resolved, she exhibited increasing dysphagia., The follow-up MRI demonstrated regression of the retro-odontoid pseudotumor [], but video fluoroscopy confirmed C5-C6 OALL resulting in esophageal obstruction. Therefore, 6 months after the original surgery, she underwent anterior C3-C6 OALL resection using a right anterior approach, diamond burrs, and an ultrasonic bone curette []. Postoperatively, the patient’s dysphagia improved quickly.