Direct rupture of hydatid cyst into the peritoneal cavity in a 50-year-old man. Contrast-enhanced axial CT scan of the upper abdomen demonstrates a partially collapsed cystic lesion (black arrow) with an irregular contour growing exophytically from the liver. It has lost its normal spherical shape. Isoattenuating detached membranes (white arrow) appear as serpentine structures within the lesion. A small amount of ascites (white arrowhead) is present.