Ultrastructural study of skeletal muscle invasion by a malignant fibrous histiocytoma

Abstract

Cancer grows by progressive invasion, infiltration and destruction of tissues surrounding primary tumors or their metastases. Although this process has been amply investigated, it has not been adequately studied by means of electron microscopy and scarce information exists about its morphological aspects; Because of these reasons, we studied the ultrastructure of skeletal muscle invasion by a malignant fibrous histiocytoma as an example of the cancer growing process.Biopsies were obtained from a mass located intramuscularly in the left thigh of a 70 years old male patient. Samples were taken from the tumor and the surrounding muscle tissue. The specimens were processed with routine techniques for transmission electron microscopy and observed in a Hitachi H-500 electron microscope.The histopathological picture of the tumor fell within the spectrum for malignant fibrous histiocytoma. The borderline zone between tumor cells and muscle tissue was carefully examined. Tumor cells were located in the extracellular space. Muscle fibers were not found invaded but those beside tumor cells exhibited several alterations including atrophy (Fig. 1) and vacuolation (Fig. 3).