Tumoral calcinosis. An ultrastructural analysis and consideration of pathogenesis.

The clinical presentation and radiographic findings including computed tomography is described in a case of tumoral calcinosis along with a detailed light- and electronmicroscopic analysis. Five main cell types surrounding the calcified masses were identified: fat cells, fibroblasts, macrophages, osteoclast-like giant cells and osteoblast-like cells. The light microscopic and ultrastructural findings suggest an initial tissue damage with fat necrosis and the secondary calcification process seems to be of the mitochondrial type and possibly also of the matrix vesicel type.