Alveolar hydatid: Radiologic-histologic correlation

Abstract

Background The aim of the present study was to study the different imaging appearances on proven cases of hepatic alveolar hydatid, which is often misdiagnosed as a tumor. Materials and Methods We studied ultrasonography, computed tomography, and magnetic resonance imaging findings in 21 histopathologically proven cases of hepatic alveolar hydatid disease over a period of 1 year. The ultrasonography findings were heterogeneous hyperechoic mass in 14 cases, multilocular cystic mass in 3 cases, and hyperechoic mass with calcification giving dense acoustics in 4 cases. Computed tomography findings were a sheet-like hypodense, infiltrative, nonenhancing mass without biliary or portal encasement or infiltration in 16 cases, biliary infiltration in 4 cases, and portal encasement in 3 cases. The magnetic resonance imaging findings showed that all 21 patients had a characteristic microvesicular appearance of the parasitic mass on T2-weighted images corresponding to the microvesicles demonstrated on histopathology. The portal encasement and biliary infiltration were also demonstrated on magnetic resonance (MR) images. Conclusions T2-weighted MR images correlate with the histologic characteristic of the hepatic alveolar hydatid disease. Ultrasonography and computed tomography may help in initial assessment of the extent of the disease, but MR helps in exact diagnosis.