This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Leak, L. V. Articles by McKhann, C. F. Search for Related Content PubMed PubMed Citation Articles by Leak, L. V. Articles by McKhann, C. F.

Electron Microscopic Studies on a Human Fibromyxosarcoma¹

General Surgical Services, Harvard Medical School and The Massachusetts General Hospital (L.V.L., J.F.B., and C.F.M.) and the James Homer Wright Pathology Laboratories of The Massachusetts General Hospital and Department of Pathology, Harvard Medical School, Boston, Massachusetts (J.B.C.)

Electron microscopic observations of tumor tissue classified as fibromyxosarcoma revealed the presence of 2 morphologically definable cell types: a dense fibroblast-like cell and a pale cell. Infrequently, cells with features common to both the dense and pale cells were observed. Both cells types contained numerous filaments, dilated cisternae, and large vacuoles with apparent degenerative cell products and membranous lamellar structures. However, the dense fibroblast-like cell contained an abundant amount of ribosomes that were attached to the endoplasmic reticulum and also in clusters in the cytoplasmic matrix while the pale cell contained a sparse distribution of endoplasmic reticulum with few ribosomes attached to its outer surface. The observation of many features that are characteristic for fibroblast suggest that the fibroblast may represent the cell of origin for the tumor cells in this study, and that the dense and pale cells represent various degrees of differentiation of a single cell type in the tumorous tissue.

An electron-dense filamentous material occupies the ground substance that surrounds the cells and frequently coats the surface of the cells. It is suggested that this material corresponds to the soft gray gelatinous substance observed grossly. Histochemical studies indicate that this substance contains acid mucopolysaccharides.

¹ Supported by USPHS Grant No. HE-0664 (HEP).

Received 5/20/66. Accepted 9/ 1/66.