Multimodal imaging in the differential diagnosis of soft tissue calcinosis

Soft tissue calcinosis is a common radiographic finding, which may be related to different types of pathological processes. Multimodality imaging, combined with analysis of clinical and laboratory data, plays an important role for the differential diagnosis of these conditions. Conventional radiography is considered the first line approach to soft tissue calcinosis; CT and MRI may provide further information to better characterize calcified deposits. Imaging may help to distinguish metabolic calcification, such as primary tumoral calcinosis and the secondary one (associated with acquired disorders of calcium or phosphate regulation), from dystrophic calcification, which is associated to normal blood values of phosphate. The sedimentation sign typical of tumoral calcinosis has been demonstrated by plain film radiography, CT, MRI, and, more recently, by ultrasonography. Other types of soft tissue calcinosis may have a degenerative, metaplastic or neoplastic origin, and their characterization strongly relies on multimodality imaging.