Ultrastructural study of a clear cell chondrosarcoma.

A lesion in the left humeral head of a 15-year-old Japanese boy was light-microscopically diagnosed as clear cell chondrosarcoma. Fresh tissues from the lesion were studied ultrastructurally. In most tumor cells, that is, clear cells, paucity of organelles, sparse free ribosomes, and low protein content in cytosol were most striking. Tumor cells had many microvilli characteristic of cartilage cells. Among scanty organelles, vesicles or cisternae of dilated rough endoplasmic reticulum were rather conspicuous, and well-developed Golgi complexes were sparse. Intercellular matrix was scanty. These results suggest that intercellular matrix substance may be synthesized substantially by rough endoplasmic reticulum, whereas the synthesized substance perhaps cannot be transported smoothly into extracellular spaces because of scanty well-developed Golgi complexes.