Human chronic Mansonian schistosomiasis-cell proliferation and fibre formation in the hepatic sinusoidal wall: a morphometric, light and electron-microscopy study.

A morphometric, light and electron-microscopy study of the sinusoids in human Mansonian schistosomiasis with and without portal hypertension showed a sequence of events beginning with an increased number of cell nuclei, particularly evident at the centrolobular region. This is followed by deposition of reticulin fibres along the perisinusoidal space. Later, increased numbers of cells and reticulin fibres are seen throughout the lobule. Other findings, such as reduplication of the sinusoidal lining and the focal appearance beneath the cell layer of the thin discontinuous membrane, were also reported. This perisinusoidal fibrosis probably adds an element of heightened intrasinusoidal pressure to the perisinusoidal hypertension already described in this disease. Its pathogenic mechanism is obscure. The hepatic sinusoids in Mansonian schistosomiasis receive mainly arterial blood. High intraluminal pressure could be one explanation of the perisinusoidal fibrosis in these cases. However, as possibly occurs in primary sinusoidal portal hypertension, chronic immunological stimulation leading to proliferation of Küpffer cells and lipocytes could be an alternative mechanism.