A form of hepatobiliary fibropolycystic disease characterized by an overgrowth of biliary epithelium and supportive connective tissue. Multiple cysts are present in the liver parenchyma. The condition is usually associated with polycystic kidney disease and congenital biliary duct disease.
Polycystic liver disease is estimated to be frequent as 1:200. Of patients referred for ultrasonographic examination of the abdomen, 2 to 5% have hepatic cysts, of which fewer than one-third are multiple with one to three cysts. Hepatic cysts are exceptionally rare in children; frequency increases from 0% in first two decades of life to 7% in the eighth decade of life.
Autosomal dominant. Polycystic liver disease occurs either alone or in association with autosomal dominant ☞Polycystic Kidney Disease.
Polycystic liver disease results from mutations PRKCSH, SEC63, and LRP5. It also arises from mutations of PKD1 or PKD2 in autosomal dominant ☞Polycystic Kidney Disease. PKD1 and PKD2 encode two ciliary proteins, polycystin-1 and polycystin-2. Polycystin-1 acts as a mechanosensor and polycystin-2 as a calcium channel. Together, these proteins regulate intracellular calcium concentrations. Alterations in the development and differentiation of bile ducts and intralobular bile ductules leads to the development of biliary microhamartomas and cysts. Cystic dilatation of peribiliary glands around the large intrahepatic bile ducts may also give rise to the cysts.
Magnetic resonance imaging in at-risk individuals or asymptomatic first-degree relatives may be the most sensitive method to differentiate a complicated cyst from an uncomplicated one. Genetic counseling and testing should be offered.
The severity of the phenotype is divided according to the height adjusted total liver volume (htTLV) into mild, moderate, and severe. Patient disease severity is classified as mild (htTLV<1600 mL), moderate (htTLV 1600-3200 mL/m), and severe (htTLV>3200 mL/m). Patients with mild polycystic liver diseases rarely develop symptoms or complications and might not seek care unless liver cysts are incidentally found on radiological imaging. Most patients with polycystic liver disease are asymptomatic and have normal liver function tests. Patients with moderate polycystic liver diseases display symptoms caused by the mass effect of one or several cysts, or by a massively enlarged liver. Hemorrhage or rupture of the hepatic cysts are rare complications that present as an acute abdomen. Infection of hepatic cyst may be indistinguishable from acute cholecystitis. Percutaneous drainage of the infected cyst is usually effective and safe and surgical drainage is reserved for patients with relapses. Patients with severe polycystic liver diseases have mass effects of large cysts and include symptoms related to the increased intraabdominal pressure, obstruction of the hepatic veins, inferior vena cava, and obstruction of the bile ducts. ...