A case series of calcium pyrophosphate deposition in the spine: An underrecognized debilitating disease.

Calcium pyrophosphate deposition (CPPD) disease is an inflammatory arthritis prevalent in elderly individuals. Spinal CPPD is uncommon, and presentation can vary widely with common clinical and radiographic mimics. We identified 9 cases of lumbar and 1 case of thoracic spinal CPPD (age range: 63-85 years; 5 male, 5 female) at our institution over a 10-year period. All presented with pain (90% chronic, 10% acute); 4 had prior instrumentation and 1 had prior trauma. CPPD was not clinically suspected in any case. Preoperative imaging diagnoses include central canal stenosis, neuroforaminal narrowing, septic arthropathy, synovial cyst, degeneration, and epidural mass/abscess. Intraoperatively, a spinal cyst was most often described. All pathologic examinations revealed purple granular calcified material with positively birefringent rhomboid crystals embedded within fibrocartilage. Following a neuropathologic diagnosis, only 2 patients received CPPD treatment. This study aims to highlight that spinal CPPD is underdiagnosed and undertreated. Although clinical presentations are variable, wider recognition of this rare disease among neuropathologists receiving spinal specimens may provide earlier diagnosis. Accurate pathologic diagnosis can improve identification, refine clinical suspicion, and facilitate management. Improved identification, particularly in elderly patients and those with prior trauma/instrumentation, will promote appropriate therapy and management.