Ultrasonographic features of pseudotumorous form of ascariasis

Abstract

We report the ultrasonographic findings of a 60 year old woman with pseudotumorous form of ascariasis. Real-time ultrasonographic examination using a curved array transducer revealed grossly thickened small bowel loops, multiple small circular deposits throughout the peritoneal cavity, and a moderate amount of ascites. The English literature on the different forms of abdominal ascariasis is reviewed. Specific signs, which include the ‘strip’ sign, the ‘four-lines’, ‘inner tube’, or ‘double tube’ sign, the ‘bull's eye’ or ‘target’ sign, a ‘worm mass’ or ‘spaghetti-like’ appearance, and the ‘zig-zag’ sign can be present in any form of abdominal ascariasis, as they represent the image of the Ascaris worms visualized under ultrasonographic examination. However, the non-specific signs are not peculiar to A. lumbricoides infections, but are results of secondary changes due to A. lumbricoides infections in the corresponding organs.