Symptomatic retro-odontoid pseudotumor causing calcium pyrophosphate dihydrate deposition combined with multilevel cervical spondylotic myelopathy

INTRODUCTION: Symptomatic retro-odontoid pseudotumor (ROP) caused by cervical compression and myelopathy is rare. Pathological diagnosis is recommended for differential diagnosis including the following: inflammatory disease, primary bone tumor, metastatic disease and calcium pyrophosphate dihydrate deposition (CPPD) also known as “crowned dens syndrome”. The authors report a rare case of ROP caused by CPPD deposition combined with multilevel cervical spondylotic myelopathy (MCSM) which was treated by tumor resectioning using a transoral approach combined with posterior decompression and fusion. CASE PRESENTATION: A 66-year-old male presented with progressive neck pain and spastic gait with no history of trauma. Radiographic imaging revealed degenerative change involving the atlanto-axial and atlanto-occipital joints with calcified enhancing soft tissue around the odontoid process causing cord compression and cervical instability at the C1-C2 level combined with MCSM and spinal cord compression at C3 to C7. Microscopic assisted transoral tumor resection combined with posterior decompression and fusion was performed at the occiput to T2. The pathology report describes a rhomboid-shaped crystal caused by calcium pyrophosphate dihydrate deposition (CPPD) disease. At the 6-month follow-up following the operation, the patient's neck pain and spastic gait were improved compared to the preoperative examination. DISCUSSION: Cervical compression and myelopathy from ROP causing CPPD combined with MCSM is rare. Pathology diagnosis and surgical management are highly recommended. CONCLUSION: In this case, a combined surgical approach: tumor resection using a transoral approach and a posterior approach for decompression and fusion at occiput to T2 was an effective option for this condition.