Cervical myelopathy from retro-odontoid calcium pyrophosphate dihydrate mass: a case report

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is one of the most common forms of crystal-associated arthropathy in the elderly. However, cervical spine is rarely affected, especially in upper cervical area. There have been previous reported cases of symptomatic retro-odontoid CPPD deposition disease in English literature but this case is the first reported in Thai patients. This is a case report of a 67-year-old man who presented with neck pain with progressive myelopathy. Neurologic examination demonstrated a cervical myelopathy with muscle weakness and sensory disturbance of both extremities. Imaging studies showed extradural retro-odontoid mass compressing the spinal cord. The patient underwent occiput to C3 fusion with plating, posterior arch of atlas resection, transoral odontoidectomy, and mass removal. Histological examination of the mass revealed fibrocartilage tissue and rhomboid shaped crystals that showed positive biferingent in polarized light microscopy consistent with CPPD crystals. After surgery, no complication was found, and his neurological function had improved.