A simple sonographic scoring system combined with routine serology is useful in differentiating parasitic from non-parasitic cysts of the liver

In the absence of a detached endocyst, unilocular echinococcal cysts of the liver may be difficult to distinguish from non-parasitic cysts. In an attempt to identify sonographic features that could help distinguish these two types of cysts, we retrospectively analyzed 64 cases of fluid-filled hepatic cysts whose parasitic nature was ultimately excluded. This experience allowed us to develop a simple scoring system that quantifies the likelihood that hepatic cysts are non-parasitic. Sonographic criteria, together with the results of standard serological testing for cystic echinococcosis, proved to be sufficiently specific to allow definitive diagnosis without resorting to further tests.