Non-fecalith-induced appendicitis: etiology, imaging, and pathology.

This study aims to document the imaging and pathology findings in non-fecalith-induced appendicitis. We reviewed the imaging and pathologic findings in 40 patients with histologically proven purulent appendicitis seen over a 2-year period. Findings documented were (1) total appendiceal involvement, (2) predominant appendiceal tip involvement, (3) presence of a fecalith, and (4) presence of lymphoid hyperplasia. There were a total of 40 patients, 28 males and 12 females. The age range was 2-18 years with a mean of 11.5 years. Twenty-two (55 %) patients demonstrated classic purulent appendicitis of the whole appendix, 20 (91 %) of these appendices had a fecalith. Eighteen (45 %) patients demonstrated purulent appendicitis confined to or predominately involving the tip of the appendix, and all 18 (100 %) patients demonstrated marked lymphoid hyperplasia. Only two (11 %) of these appendices had a fecalith. Overall, a fecalith was found in only 55 % of our cases, while 45 % demonstrated no fecalith, but rather marked lymphoid hyperplasia. Lymphoid hyperplasia appeared to be the underlying predisposing cause of purulent appendicitis in these cases.