[Ultrasound signs of pseudoneoplastic forms of hepatic hydatid cysts. A prospective analysis of 50 cases].

Pseudoneoplastic hydatid cyst of the liver (type IV), still raises diagnostic difficulties on ultrasonography (US), and often leads us to perform computed tomography. We therefore, conducted a prospective study of 50 cases of hepatic hydatid cyst (HHC) type IV in order to define the US and Doppler features allowing easy diagnosis with the best cost-effectiveness ratio. HHC type IV represented 23.7% of all types. The average age was 43.5 years with a female predominance. Many signs were described and their frequency was established. The main signs were daughter cysts (82%), hypo or hyperechoic spirals (66%), and peripheral transonic collarette (54%). At least one of these signs was present in 90% of cases. The Doppler study showed the avascular nature of the lesion in 100% of cases. Hydatid serology using modern immunologic techniques confirmed the diagnosis in 74% of cases. The US-serology combination can establish the positive diagnosis of HHC type IV in 94% of cases. Computed tomography therefore has a small place in this setting.