Calcium pyrophosphate dihydrate crystal deposition disease of the spinal dura mater: a case report

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by the accumulation of CPPD crystal in articular and periarticular tissues, but CPPD crystal deposition along the spinal dura mater has not been previously reported. We report a 54-year-old male presenting with progressive neck pain and numbness of the extremities. CT showed diffuse dorsal epidural calcification from C3-T6 which resulted in spinal canal stenosis. On MR imaging, the lesion was hypointense on both T(1) and T(2) weighted images. From these findings, CPPD crystal deposition in the ligamentum flavum was suspected preoperatively. Biopsy at the level of C5-6 were performed to confirm the diagnosis. Perioperative and histopathological findings revealed that CPPD crystals were deposited along the dorsal dura mater, not in the ligamentum flavum. We firstly report the CT and MR imaging features of a possible new concept in the differential diagnosis of CPPD crystal deposition disease.