Acute appendicitis presenting as unusual left upper quadrant pain.

Appendicitis is the most common abdominal disease that requires surgery in the emergency ward. It usually presents as right lower quadrant pain, but may rarely present as left upper quadrant (LUQ) pain due to congenital anatomical abnormalities of the intestine. We report a patient who complained of persistent LUQ abdominal pain and was finally diagnosed by computed tomography (CT) as congenital intestinal malrotation complicated with acute appendicitis. It is important to include acute appendicitis in the differential diagnosis of patients who complain of LUQ abdominal pain. Abdominal CT can provide significant information that is useful in preoperative diagnosis and determination of proper treatment.