Intradural calcium pyrophosphate dihydrate deposition disease: case report.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease, also known as pseudogout, is a crystalline arthropathy that usually affects large joints and periarticular tissue. Spinal involvement is rare and is usually limited to extradural articular and periarticular structures. Only one case of intradural disease has been previously reported. The authors report the second known case of intradural CPPD deposition disease. An 81-year-old man presented with an 8-week history of urinary and fecal incontinence on the background of long-standing back pain, lower-limb paresthesia, and a known L1 calcified intradural extramedullary mass. Slow growth of the L1 lesion had been documented over several decades on serial CT and MRI. A T12-L2 laminectomy and gross-total resection of the mass was performed. Histopathology demonstrated polarizing rhomboid-shaped crystals consistent with CPPD deposition disease. The patient had significant improvement in bowel and bladder function 6 months postoperatively and made a full recovery. The pathophysiology of intradural involvement remains uncertain. Further case series are required to clarify the true incidence and prognosis of the condition.