Cystic echinococcosis of the liver

Background

Cystic echinococcosis (CE) is a widely endemic helminthic disease caused by infection with metacestodes (larval stage) of the Echinococcus granulosus tapeworm, which is transmitted by dogs and found on every continent, except Antarctica. This study aimed to review the life cycle, epidemiology, symptoms, diagnostic methods, and treatment of E granulosus infection of the liver.

Methods

A comprehensive review was conducted using MEDLINE/PubMed, Google Scholar, Cochrane Library, and the Web of Science, which were accessed between 1990 and 2024. The main search focused on “CE of the liver.” The following terms were used: cystic echinococcosis, hydatidosis, E granulosus, echinococcus life cycle, liver cyst, albendazole, liver resection, pericystectomy, cystobiliary fistula, and percutaneous aspiration injection and reaspiration (PAIR).

Results

CE should be considered in the differential diagnosis of hepatic cysts, especially among individuals with risk factors, such as those who have traveled to or immigrated from areas with a high prevalence. Echinococcus species require 2 hosts to complete their life cycle, with humans acting as intermediate hosts that become infected by ingesting eggs from contaminated environments, leading to cyst formation, typically in the liver or lungs. Symptoms are based on cyst size and location, such as abdominal pain, jaundice, respiratory distress, or neurologic deficits, and can lead to severe complications, such as cyst rupture, allergic reactions, sepsis, or secondary hydatidosis. Imaging plays a key role in evaluating cyst stage, size, location, and potential complications and in determining the appropriateness of a minimally invasive PAIR procedure. Although serum antibody tests typically have a low sensitivity, antigen assays or recombinant proteins may provide useful diagnostic information. For uncomplicated active cysts, the treatment options include chemotherapy alone or in combination with the PAIR technique.

Conclusion

Hepatic echinococcal cysts, which are relatively rare in North America, should be considered in the differential diagnosis of hepatic cysts, especially in individuals with risk factors.