**4.1 Clinical features**

Humans remain asymptomatic for a prolonged period of time after being infected due to the slow growth of the hydatid cyst in the liver (1–5 mm per year). Small and medium cysts of central hepatic location are usually asymptomatic, or a slight pain in the epigastrium and right hypochondrium might be reported by the patient, together with a sensation of abdominal discomfort. Besides, the previous immune status of the patient and the anatomical location of the cyst could determine a late manifestation of the first symptoms [26]. When the cysts grow and reach a significant size, the mass effect on the bile tree and hepatic vasculature determine other clinical manifestations derived from biliary obstruction, portal hypertension, and Budd-Chiari syndrome. The magnitude of this effect will determine different degrees of jaundice and portal hypertension, which may range from a slight increase of bilirubinemia and the appearance of venous collaterals of the abdominal wall to very severe jaundice, ascites, and upper digestive hemorrhage secondary to rupture of the gastroesophageal varices [27].
