Introduction Echinococcosis is an infection which occurs due to larval form of Echinococcus multilocularis which causes lveolar echinococcosis . The infection behaves as a slow-growing malignant tumor. Initially, it is located in the liver and then may spread to any other organ through metastases. Alveolar echinococcosis is a chronic disease with a presymptomatic stage that may last for years before signs and symptoms develop. Symptoms Clinical signs include weight loss, abdominal pain, general malaise and signs of hepatic failure. If left untreated, alveolar echinococcosis is progressive and fatal. Pathophysiology Alveolar echinococcosis is a chronic disease with a presymptomatic stage that may last for years before signs and symptoms develop. The variability of the signs and symptoms depends on the location of the lesions (see image below), which may develop in the liver and/or in various organs or tissues, especially the lungs, brain, and bones. Epidemology Untreated alveolar echinococcosis is usually fatal. The survival rate at 5 years in untreated patients averages 40%. Therapeutic approaches that have been developed since the early 1980s have markedly improved the prognosis of the disease. The actuarial survival rate at 5 years was 88% in a series of 80 patients observed from 1983-1993.