PMC5981182_01
Initial sagittal (a) and coronal (b) computed tomography scan obtained at presentation demonstrate a non-enhancing mass centered along the posterior aspect of the clivus and C2, eccentric to the right, with soft tissue air. Not associated with erosive bony changes of either the dens (c) or the body of C2 (d)
SNI-9-100-g001.jpg
PMC5981182_01_SNI-9-100-g001.jpg
F1
Computed tomography (CT) and magnetic resonance imaging (MRI) were performed and showed a non-enhancing soft-tissue mass extending superior from the retro-clivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction [Figures 1 and 2].
Sagittal T1-weighted (a) and axial T2-weighted (b) magnetic resonance imaging demonstrate a soft-tissue mass posterior to C2. The soft-tissue mass exerts severe mass effect on the upper cervicalmedullary junction with associated abnormal cord signal
SNI-9-100-g002.jpg
PMC5981182_01_SNI-9-100-g002.jpg
F2
Computed tomography (CT) and magnetic resonance imaging (MRI) were performed and showed a non-enhancing soft-tissue mass extending superior from the retro-clivus to C2 posteriorly, eccentric to the right with severe mass effect on the upper cervical medullary junction [Figures 1 and 2]. There is low signal on T2/FLAIR. The non-vascular pannus and calcium pyrophosphate deposition [Figure 2] may appear similar to findings that are characteristic of CAPNON lesions.
Postoperative T1-weighted sagittal (a) and axial (b) magnetic resonance imaging demonstrate interval postoperative changes including partial debulking of the mass and evidence of the fat graft. There was improvement of the cord kinking at the cervical medullary junction, but persistent moderate canal stenosis. Lateral x-ray films demonstrate a stable construct (c)
SNI-9-100-g003.jpg
PMC5981182_01_SNI-9-100-g003.jpg
F3
Examination under polarized light revealed focal apple green birefringence to polarized light [Figure 3].
Hematoxylin and eosin (H and E) stain reveals amorphous, eosinophilic deposits (a). Congo red stain under polarized light shows obvious apple green birefringence (b)
SNI-9-100-g004.jpg
PMC5981182_01_SNI-9-100-g004.jpg
F4
CT imaging demonstrated a stable spine construct [Figure 4].
A 2-year postoperative MRI demonstrating complete resolution of retroclival lesion as well as no spinal cord compression
SNI-9-100-g005.jpg
PMC5981182_01_SNI-9-100-g005.jpg
F5
There was no evidence of spinal cord compression [Figure 5].