Ultrastructure of a mixed form of calcinosis

An unusual form of calcinosis is described presenting a joint occurrence of calcinosis circumscripta and calcinosis universalis. Ultrastructurally, the mineral constituent is of much higher crystallinity than that of normal bone, and includes a rare kind of carbonate apatite. The crystals of the specimen were needle-like and hexagonal, in juxtaposition to normal collagen fibrils. Supposedly, the development of the calcifiable matrix is different in calcinosis and bone tissue.