Parosteal osteogenic sarcoma. Ultrastructural observations in three cases.

Ultrastructural study of three parosteal osteogenic sarcomas showed this type of tumor to contain numerous myofibroblasts. These cells were admixed with occasional cells resembling osteoblasts and fibroblasts. Cartilaginous areas showed the typical arrangement of cartilage cells embedded in a dense collagen matrix.

Osteogenic sarcoma: a study of the ultrastructure.

Ultrastructural examination of 26 osteogenic sarcomas has revealed that in addition to the basic osteoblast comprising the tumor, five additional cell types may be identified. These include chondroblasts, osteocytes, undifferentiated cells and myofibroblasts. The latter cell type has not been reported in previous studies of medullary osteosarcomas.

Malignant soft tissue tumors (malignant fibrous histiocytoma, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma): an electron microscopic study.

A comparative ultrastructural analysis of malignant soft tissue tumors (malignant fibrous histiocytoma, pleomorphic liposarcoma, and pleomorphic rhabdomyosarcoma) revealed similar ultrastructural features in this group of tumors. However, by electron microscopy these tumors can be differentiated on the basis of cytoplasmic and extracytoplasmic features (myosin filaments, lipid droplets, and perinuclear intermediate filaments, for example). This is even true of less well differentiated tumors and tumor cells.