Long-term Sonographic Follow-up of inactive echinococcal cysts located to the liver.

The sonographic classification of echinococcal cysts proposed by the WHO Informal Working Group on Echinococcosis (WHO-IWGE) allows the distinction between active, transitional and inactive cysts, thus facilitating selection of treatment modalities. For uncomplicated, inactive cysts (CE4, CE5), recent expert opinion recommends they should be left untreated and monitored, but no data exists on the safety and effectiveness of this approach. To fill this gap, we report our experience with long-term sonographic monitoring of inactive cysts. Records of patients who presented at our clinic and were diagnosed with inactive echinococcal cysts of the liver were searched. Inclusion criteria were: • presence of cysts exclusively in inactive stage at the time of diagnosis; • follow-up with abdominal ultrasound performed every 6 or 12 months; • minimal length of follow up of 24 months. For each patient, demographic details, characteristics of the cyst within the liver and complications and sonographic changes if they occurred during follow-up were obtained. From March 1994 to May 2011, 94 patients with exclusively inactive liver cysts were seen in our clinic with 41 meeting all inclusion criteria. 16 patients were male and 25 were female (mean age at time of diagnosis: 48 years, range: 14-86 years). They harbored a total of 55 cysts (of which 33 were CE4 type and 22 were CE5 type). The average cyst diameter was 52 mm. 27 patients had 1 cyst each, 14 patients had 2 cysts each. 42 cysts were located in the right lobe, 4 in the left lobe and 9 in the fourth segment. The mean follow-up period was 78 months (range: 24-453 months) and in 40 patients (97.6%) the cysts remained in the inactive stage (reactivation occurred only in 1 patient). Our observations indicate that a proportion of cysts become completely inactive without any treatment and cysts that reached this stage are likely to remain inactive over time. Our data suggest that “Watch and Wait” may be a viable management option for uncomplicated inactive liver cysts.