Diagnosis of appendicitis: imaging findings in patients with atypical clinical features.

Acute appendicitis is usually diagnosed on the basis of signs, symptoms, and results of simple laboratory tests. However, in patients with atypical clinical features, imaging studies play a significant role in preoperative diagnosis and determination of proper treatment. In this pictorial essay, we present a spectrum of imaging findings in patients whose clinical features were unusual because of the abnormal position of the appendix, the presence of other illnesses, or the presence of complications in children. Appendicitis was not initially considered on clinical presentation in any of our cases. In most cases, the correct diagnosis of appendicitis was made or, at least in retrospect, could have been made on the basis of imaging findings.