Adenoviral appendicitis presenting clinically as acute appendicitis.

The vermiform appendix may react as part of a generalized viral infection, but histological documentation of appendiceal viral infection is rare. Adenovirus has been described in association with mesenteric adenitis and ileocecal intussusception, but to our knowledge there are no well-documented cases of adenoviral appendiceal infection presenting clinically as acute appendicitis without intussusception. We reviewed the pathology records of all appendectomies performed at our institution from 2001 through 2005. All incidental appendectomies and appendices with acute appendicitis or other pathological findings were excluded. We selected all negative appendices with lymphoid hyperplasia and reviewed hematoxylin and eosin-stained slides. Representative sections of each of these cases were immunostained with adenovirus antibody. Eight hundred seventy-seven appendectomies were performed during the study period. Of these, there were 94 cases that had a clinical diagnosis of acute appendicitis and that were pathologically negative. Sixty-three of the 94 cases had lymphoid hyperplasia and were stained for adenovirus. We identified 2 positive cases, which also showed epithelial proliferation and viral inclusions. One involved a 6-year-old male and the other involved a 5-year-old female, without intussusception. Adenovirus can infect the appendix and clinically mimic acute appendicitis without intussusception. We recommend that all negative appendices be evaluated for lymphoid hyperplasia and epithelial viral changes and possibly be stained with immunoperoxidase staining if indicated. We speculate that adenovirus may play a role in the pathogenesis of acute appendicitis.