Retroodontoid pseudotumor: Two cases of intradural ganglion cysts arising from the odontoid process with syringobulbia.

Abstract Background Ganglion cysts mostly occur in the knuckles and wrists, but they rarely present in the odontoid process and can cause neurological symptoms by compressing the spinal cord. They are mostly localized in the epidural space, but may very rarely appear in the intradural space. There are no reports of cases of intradural ganglion cyst involving syringobulbia. Case Description We report the presentation and management of two cases of an intradural ganglion cyst of the odontoid process. Several treatment options for ganglion cysts of the odontoid process have been reported, such as rest and use of a neck collar, posterior decompression and fusion, and transoral anterior decompression. Because our two cases progressed rapidly and had severe neurological symptoms, surgical treatment was performed for rapid decompression and definitive pathological diagnosis. The mass was resected as much as possible using the lateral occipital fossa approach, and the operation was completed without dissection of the brain stem or manipulation of the syringobulbia. Postoperatively, neurological symptoms promptly improved, and the syringobulbia reduced. Conclusions For intradural ganglion cysts with syringobulbia, we suggest relief of the compression by resection of the mass and syringobulbia should be treated in two stages if necessary, to avoid the risk of damage to the brainstem.