Calcium pyrophosphate dihydrate crystal deposition disease.

Calcium pyrophosphate dihydrate (CPPD) crystal deposition disease is characterized by the accumulation of pyrophosphate dihydrate crystals in articular and periarticular tissues. Various terms have been utilized to describe this arthropathy, which has led to some confusion. CPPD crystal deposition disease is among many conditions that may result in crystal deposition within cartilage. Chondrocalcinosis is a pathologic and radiographic term denoting calcification of cartilage within joints including both hyaline articular cartilage and fibrocartilage. Pseudogout is a clinical term applied to an acute inflammatory process in a joint(s) mimicking a gout attack. Pseudogout is just one of the multiple clinical presentations for CPPD crystal deposition disease. Pyrophosphate arthropathy is a term that has been used to describe the peculiar pattern of joint destruction associated with CPPD crystal deposition disease. This article reviews the protean manifestations of CPPD crystal deposition disease with emphasis on diagnostic imaging.