Ultrastructural and crystallographic study of calcifications from a patient with CREST syndrome.

An ultrastructural and crystallographic study was done on calcium deposits obtained from a patient with the CREST syndrome. Optical microscopy showed that large calcific cutaneous deposits seemed to have developed in a dense connective tissue without any inflammatory reaction. The oldest lesions contained heterotopic bone. Electron microscopy showed that calcium deposit, in the slightly mineralized fibers, was located at the center of the elastic fibers. The calcifications were surgically removed and studies were performed on the rough products and, after heating, using x-ray crystallography, differential thermal analysis and quantitative chemical analysis. Our results showed that this cutaneous calcification is a B type carbonated apatite.