[Hydatid cysts of the liver appearing late (10 to 22 years) after surgical treatment of pulmonary hydatidosis. Physiopathologic problems].

The very late observation of an hydatid cyst of the liver, after clinical or fortuitous signs (intraoperative, ultrasound, CT) is a highly underestimated possibility. From 4 cases of hydatid cysts of the liver which were removed 10 to 22 year after a pulmonary hydatidosis, any possibility of parasitic reinfestation during this time being excluded, the authors propose a physiopathological explanation to an often very long clinical latency period of the liver hydatidosis. Indeed the pulmonary location of the hydatid disease means that the hepatic filter did not properly operate or was bypassed, but it does not exclude a simultaneous intrahepatic graft. The literature study shows a 4 to 8.4% rate of concomitant liver-lung location according to the statistical data provided by thoracic and digestive surgery departments. The percentage reaches 25% when ultrasounds and abdominal computed tomography are systematically used. The rapid growth of the hydatid cyst in the lung can be explained by the low resistance of the lung parenchyma and vasculo-bronchial structure to the intracystic pressure, whereas in the liver, the hydatid cyst growing is stopped by a dense parenchyma and the hepatobiliary capsules. When fissuring or large opening in the biliary tract occurs the intracystic pressure drops, the pericyst becomes sclerotic, calcified. The combination of these different factors all the more contributes to the cyst involution since it presents a central topography.