Appendiceal abscess mimicking infected urachal cyst in a child with intestinal malrotation

An appendiceal abscess with intestinal malrotation can occur anywhere in the abdomen, not only in the right lower quadrant. We report a case presenting a midline mass of the lower abdomen whose computed tomography (CT) and ultrasonography (US) findings mimicked a urachal abscess. A retrospective review of CT findings led to the correct diagnosis by showing malposition of the ascending colon.