Fat-containing lesions revealed by CT in children with right lower quadrant pain

Suspected appendicitis is the most common indication for emergent abdominal surgery in children. The clinical diagnosis of appendicitis can be challenging, and CT is playing an increasing role in the evaluation of right lower quadrant pain. Occasionally, alternative diagnoses to appendicitis can be suggested on CT. The appreciation of a fat-containing lesion in the right lower quadrant will often allow a specific diagnosis. Importantly, many of these lesions are self-limited and treated nonoperatively. The purpose of this pictorial essay is to illustrate the spectrum of fat-containing lesions that can present as alternative diagnoses to appendicitis on CT scans performed for the evaluation of right lower quadrant pain in children.