Surgical pathology of acute appendicitis.

Pathologic findings and clinicopathologic correlations in 276 consecutive appendectomies performed in a university hospital are reviewed. In 59 cases, appendectomy was incidental to another elective procedure. In the other 217 cases exploration was performed as an emergency, and acute appendicitis was present in 160 of the cases (74 per cent); 54 of these were complicated by perforation. In the remaining 57 cases there was either some other pathologic process clinically distinct from appendicitis or no identifiable source of the preoperative symptoms. The major findings were as follows: (1) Although appendicitis appears to be the result of initial mucosal injury, not all inflamed appendices show clear evidence of lumen obstruction by a fecalith or another mechanism. (2) Perforation, which greatly increases the morbidity in appendicitis and disproportionately affects children, is the consequence of transmural necrosis and is related much more to prolonged symptoms prior to surgery than to the presence of a fecalith or any other evidence of lumen obstruction. (3) The clinical course of appendicitis varies enormously, and the duration of symptoms has a wide range that is partly independent of the pathologic findings (which may include evidence of considerable chronic inflammation). The conclusions are that the current widely accepted practice of prompt exploration on suspicion of appendicitis is fully justified, that the inflammation in appendicitis may have quite different rates of progression from patient to patient, and that the etiopathogenesis of appendicitis may not be uniform and in some cases may involve important immunologic factors.