PMC9610526_01
Serial magnetic resonance imaging scans before and after conservative management with the use of a soft collar illustrating resolution of a large atlanto-occipital cyst secondary to severe arthritis. Sagittal T1-weighted sequences at presentation (a), before immobilization (b), and at 3-month follow-up (c) showing complete resolution of a large atlanto-occipital cyst. Axial T2-weighted sequences at presentation (d), before immobilization (e), and at 3-month follow-up (f) showing resolution of initial brainstem compression. Sagittal T1 contrast-enhanced sequences at presentation (g) and before immobilization (h) showing atlanto-occipital cyst with an enhancing capsule causing significant brainstem compression and medullary kinking (circled in red is the atlanto-occipital cyst).
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F1
At that point, the cervical magnetic resonance imaging (MRI) scan showed an anterior atlanto-occipital cyst that filled the anterior foramen magnum and caused marked ventral brainstem and upper cervical spinal cord compression [Figure 1] but without intrinsic cord edema/myelomalacia. This improvement correlated with the 1-year follow-up MRI that demonstrated complete spontaneous regression of the atlanto-occipital cyst with no further evidence of kink/compression of the brainstem at the cervicomedullary junction [Figure 1].