Sinusoidal changes in extratumoral liver tissue. Report of a case of metastatic liver small cell carcinoma with collagen IV detection and ultrastructural studies.

Biopsy sections taken from liver tissue near and far away from metastases were investigated histologically, histochemically, electronmicroscopically and immunohistochemically in order to establish collagenization and extracellular matrix (ECM) formation in the space of Disse. Extratumoral tissue far away from metastases showed perisinusoidal fibrosis (van Gieson positive), moderate immunoreaction with anticollagen IV antibody, and expressed collagen formation in the space of Disse. Liver tissue near metastases showed strongly expressed paratumoral fibrosis and moderate perisinusoidal fibrosis, dilatation of Disse space with discontinuous basement membrane (BM) formation, and a lot of collagen bundles. Ito cells acquired features of transitional cells (TSC) or myofibroblast (MF)-like cells. Based on these results it is concluded that there were sinusoidal changes in extratumoral tissue, probably provoked by some cytokines released from tumoral cells.