Ultrasound Findings of Lymphoid Hyperplasia of the Appendix in Children: Differentiation from Acute Appendicitis

ABSTRACT

PURPOSE: To evaluate the ultrasound (US) findings that can help differentiate lymphoid hyperplasia in the appendix from acute appendicitis. MATERIALS AND METHODS: A total of 1230 patients (below 20 years old) suspected of having appendicitis received an appendectomy between November, 1999, and March, 2008, with US findings in 27 patients with pathologically proven lymphoid hyperplasia of the appendix. Of 167 patients that received an appendectomy from January, 2007, to December, 2007, 52 patients with acute appendicitis were retrospectively reviewed as a control group. Retrospective review of US images was performed by two radiologists who were blinded to the pathologic results. The review was based on 12 ultrasonographic criteria derived from reports on the diagnostic findings of the appendicitis. RESULTS: Compared with acute appendicitis, lymphoid hyperplasia in appendix had a smaller diameter (7.14+/-1.22 mm vs 9.37+/-1.80 mm, p < 0.001) and less wall thickening (1.38+/-0.36 mm vs 1.74 +/- 0.56 mm, p =0.001). Periappendicular inflammation (p < 0.001), intraluminal air (p = 0.006), round shape in transverse scan (p = 0.002), increased blood flow on color Doppler US (p = 0.03) were also different. CONCLUSIONS: US is a useful modality to differentiate lymphoid hyperplasia in the appendix from acute appendicitis.