Study Design Case report and review of the literature. Objective A 
retro-odontoid mass is a rare cause of cervical compression and myelopathy. The 
differential diagnosis includes the following: metastatic disease, primary 
tumor, collagen disorder, or inflammatory disease. Calcium pyrophosphate 
dihydrate (CPPD) deposition has been referred to as "crowned dens syndrome" when 
there are periodontoideal calcifications. There are only a few reported cases 
where CPPD presents as a cystic retro-odontoid mass in the atlanto-dens 
interval. In previous descriptions of surgical intervention, transoral resection 
of the mass is associated with significant morbidity and usually requires 
stabilization. The objective of this article is to report a case of an unusual 
presentation of CPPD disease of C1/C2, where we used a novel, minimally invasive 
surgical technique for decompression without fusion. Patients and Methods An 
83-year-old female patient presented with progressive cervical myelopathy over a 
3-month period. Computed tomography and magnetic resonance imaging demonstrated 
a cystic odontoid mass with a separate retro-odontoid compressive mass. A novel, 
minimally invasive transoral aspiration was performed. Histologic confirmation 
of CPPD was obtained. Results Postop imaging showed satisfactory decompression, 
which was maintained at the 6-month follow-up. This correlated with clinical 
improvement postop and 6-month follow-up. Conclusion CPPD in the atlanto-dens 
interval may present as a cystic retro-odontoideal mass and should be included 
in the differential. We used a transoral minimally invasive approach to aspirate 
the cyst. This novel technique avoided the need for a stabilization procedure or 
morbid transoral resection and provided excellent results immediately and at 6 
months.