Sonographic differential diagnosis of right lower quadrant pain other than appendicitis.

Most patients presenting with right lower quadrant pain are clinically suspected to have acute appendicitis. However, sonographic findings other than appendicitis are detected in patients who are referred for ultrasound to rule out appendicitis. This pictorial essay delineates a number of unsuspected pathological conditions revealed by ultrasound examination of the right lower quadrant that do not involve the appendix but closely mimic acute appendicitis. Imaging studies play a significant role in preoperative diagnosis and determination of proper treatment. The patient can undergo triage for proper further workup and surgical versus nonsurgical management. Acute appendicitis initially was considered on clinical presentation in all of our patients. The correct diagnosis of other pathological conditions was made on the basis of sonographic findings.