Bile-duct destruction and collagen deposition: a prominent ultrastructural feature of the liver in cystic fibrosis.

To study the liver disease of patients with cystic fibrosis, percutaneous liver biopsies were performed in 10 patients with cystic fibrosis aged 6 to 22 yr. Nine of 10 patients had high Shwachman scores, eight had normal serum levels of transaminases. Light-microscopical examination showed steatosis in seven cases and in five slight or moderate inflammatory infiltration. Eight patients showed varying degrees of fibrosis and even cirrhosis. Six patients had bile-duct proliferation and, in one case a bile plug was found. Other signs of cholestasis were not seen. Electron-microscopical investigation showed no specific signs of cholestasis such as ductal plugs or intracellular bile pigments. The canaliculi were not dilated, except in one case. Most patients had bile-duct cells with irregular shapes, protruding into the lumen, and some cases even had necrotic cells. Around the bile ducts and ductules, collagen was deposited and fat-storing cells were a common finding. Our findings do not support the view that cholestasis is the pathogenetic factor in liver disease in cystic fibrosis. A cytotoxic influence on the biliary cells, stimulating collagen deposition, seems more likely.