A CASE OF MESENCHYMAL CHONDROSARCOMA OF THE ORBIT

Abstract
A case of mesenchymal chondrosarcoma occurring in the right orbit of a 84 yr old Japanese female was reported. The ultrastructural findings of tumor are composed of 3 cell types: well-differentiated cartilaginous cells, undifferentiated cells and transitional cells. The well-differentiated cells showed scalloped cytoplasmic membranes, numerous mitochondria showing dense electron matrix, various sized lipid granules, and an abundant extracellular matrix. The extracellular matrix were collagen fibers and ground substances and matrix vesicle. The undifferentiated cells showed smooth cytoplasmic membranes, large nuclei resembling primitive mesenchymal cells.