Intranuclear Undulating Membranous Structures in Cells of a Human Parosteal Osteosarcoma

Abstract

Large numbers of paracrystalline undulating membranous structures (UMS) were observed in the nuclei of dense cells in a human parosteal osteosarcoma. The electron-dense walls of the structures were 15–20 nm thick, and circular profiles had an outer diameter of 60–70 nm and an inner diameter of 25–30 nm. The UMS-containing cell nuclei displayed a number of other characteristic features, including vermicellar bodies, large numbers of interchromatin granules, and prominent perichromatin granules. The possible significance of these features is discussed.

Key Words:

• undulating membranous structure
• paracrystalline undulating array
• parosteal osteosarcoma
• ultrastructure
• vermicellar bodies