ULTRASTRUCTURE OF HEPATIC METASTASES FROM A COLON LEIOMYOSARCOMA

The electron microscopic examination of biopsies from liver metastases of a colon leiomyosarcoma showed the existence of alterations not pre viously reported in primary tumors of that kind. Those abnormalities i ncluded proliferation of lysosomal structures as multivesicular bodies , myelin-like figures, lipofuscin granules and autophagic vacuoles, al ong with mitochondrial changes as concentric and vesiculated cristae, and presence of dense granules and elongated inclusions. This study su ggests that, in this tumor and host tissue, the so-called invasive phe notype, which is supposed to form the metastases, could have a distinc t morphological picture at the ultrastructural level.