The Non-operative Management of Asymptomatic Liver Hydatids: Ending Echinococcophobia

Cystic echinococcosis is common in many countries and involves the liver in 75% of cases. The current belief is that all incidentally discovered asymptomatic liver hydatids must be subjected to some types of interventional treatments pre-emptively for fear of some presumably impending complications. We conducted this study to assess the prognosis of patients with liver hydatids without any surgical interventions. Furthermore, we tried to predict the outcome of the cyst using two radiological signs.

Of 434 asymptomatic patients with liver cysts who referred to our center, 297 were found eligible to be monitored at 1-3-year intervals by unenhanced computed tomography (CT) over a 20-year period. The patients were given the option of either having their cysts removed by open operation (the surgical group) or entering an open-ended "watch-and-wait" program (the surveillance group). Using unenhanced CT, cyst size, laminated membrane detachment (LMD), and pericyst degenerative changes (PDCs) were evaluated every 1-3 years. If a complication happened or the cyst size increased during the follow-up period, the cyst outcome was considered "unfavorable"; otherwise, it was considered "favorable."

Forty-three patients with 56 liver cysts were operated upon without morbidity or mortality. One hundred and twenty-seven patients with 137 cysts were followed. After a median follow-up of 6 (IQR 3 to 10) years, 111 (81.0%) had favorable outcome and 26 (19.0%) cysts had an unfavorable outcome. The size of 69 (50.4%) cysts with favorable outcome was not changed. It was decreased by a mean of 35.7% (SD 17.5%) in 34 (24.8%) cysts; 8 (5.8%) cysts disappeared. Of 26 cysts with unfavorable outcome, 8 (5.8%) developed complications (6 fistulas and 2 secondary infections) after a median follow-up of 6.5 (IQR 2.3 to 12.8) years. The size of the remaining 18 cysts increased by a mean of 42.2% (SD 29.5%). Albendazole administered at a dose of 400 mg, po, bid for 3 years, had a significant effect on hydatids. After adjustment for cyst size at diagnosis and patient's age and sex, logistic regression analysis showed that being univesicular (OR 6.00, 95% CI 1.32 to 27.29), having LMD (OR 5.51, 95% CI 1.03 to 29.43), and the presence of PDCs (OR 4.25, 95% CI 1.36 to 13.30) were independent predictors of a favorable outcome for a cyst.

More than 80% of asymptomatic liver hydatids have a favorable outcome without pre-emptive surgical interventions. The presence of LMD at any stage and/or PDCs of any grade justifiably exempts asymptomatic univesicular liver hydatids from any treatments. Those without LMD or PDCs can be effectively managed with long-term albendazole, artificially inducing larval involution.