The scanning electron microscope as a diagnostic tool in liver pathology.

Diagnostic scanning electron microscopic (SEM) investigations can be performed in human liver biopsies after perfusion fixation. For needle and wedge biopsies transparenchymal perfusion techniques have been developed. The perfusion fluid is brought into the tissue through special cannulas and removed by suction. By means of this 'push and pull' method, a directional flow is achieved and the tissue specimens are cleaned of blood. Thus the inner surfaces of the parenchymal tissue are accessible and can be observed with SEM. Vascular changes in different liver diseases, such as sinusoidal stenosis or sinusoidal capillarization, are easily detectable. New aspects are obtained on the morphology, arrangement and the functional role of perisinusoidal cells during mesenchymal reaction. This gives new insights into the pathophysiology of the microcirculation. SEM is also of great significance in diagnosing liver tumours. It may aid in deciding the origin and differentiation of carcinomas or sarcomas. Moreover, for the first time the sinusoidal haemangioendothelioma , consisting of fenestrated sinusoidal cells, could be demonstrated with SEM. Cholestasis can be diagnosed with SEM. However, we were unable to obtain useful information with SEM for the differential diagnosis of intra- and extrahepatic cholestasis.