A comparative ultrastructural study of mesenchymal chondrosarcoma and myxoid chondrosarcoma

This electron microscopic study concerns an extraskeletal mesenchymal chondrosarcoma and a myxoid chondrosarcoma of bone. The well-differentiated cartilaginous cells of mesenchymal chondrosarcoma and myxoid chondrosarcomatous cells showed many features common to chondrocytes, such as abundant rough endoplasmic reticulum, multiple well-developed Golgi complexes, and microvillous and scalloped cytoplasmic membranes. Glycogen deposit was more abundant and more frequently found in the myxoid chondrosarcoma. The extracellular matrix of well-differentiated areas of mesenchymal chondrosarcoma consisted of amorphous material, electron-dense granules, tropocollagen fibrils, and collagen fibrils. The matrix of the myxoid chondrosarcoma, however, contained only the first three elements, but not collagen fibrils. The undifferentiated portion of mesenchymal chondrosarcoma showed primitive mesenchymal cells and fibroblast-like cells. This finding confirms the suggestion of Lichtenstein and Bernstein19 that undifferentiated elements of mesenchymal chondrosarcoma are in fact “precartilage mesenchyme.” Cancer 33:1531–1542, 1974.