Alveolar echinococcosis in a 28-year-old woman. (a) Axial unenhanced CT image shows an infiltrative tumor-like hepatic mass involving both lobes of the liver with irregular margin and heterogeneous contents including hyper-attenuating foci of calcification scattered peripherally and an area of hypo-attenuation corresponding to necrosis and parasitic tissue centrally. (b) Post-contrast arterial phase shows a non-enhancing, hypo-attenuating lesion. (c) Post-contrast portal-venous phase shows a faint enhancement of fibro-inflammatory components surrounding the parasitic pseudo-cyst.