The Role of Adenovirus Immunohistochemistry in Acute Appendicitis in Children

Acute appendicitis is the most common indication for emergent surgery in children and is due to a nonspecific obstruction of the appendiceal lumen. Rare reports have linked the association of adenovirus infection presenting with intussusception with acute appendicitis due to a secondary lymphoid hyperplasia leading to obstruction.

The goal of this study is to evaluate the prevalence of adenovirus infection by immunohistochemistry (IHC) (clone 20/11 & 2/6, Cell Marque) in an unbiased cohort of appendectomies due to acute appendicitis in children performed during 1 calendar year.

421 appendectomies with acute appendicitis (group 1) were included in the study with a median age of 10 years (range: 1-17) and with a male predominance (61%). Additionally, 19 appendectomies performed during an ileocolic intussusception without acute appendicitis (group 2) were included, presenting with a median age of 1 year (range: 3 months-21 years) and a female predominance (63.2%). All group 1 cases showed transmural and periappendiceal acute inflammation, which was absent in all group 2 cases. Adenovirus IHC was negative in all cases in group 1 but positive in 7 cases (36.8%) in group 2. All cases with a positive adenovirus IHC show viral cytopathic changes within the surface epithelium, consistent with adenovirus.

In this unbiased cohort of pediatric patients with acute appendicitis, adenovirus infection, as detected by IHC, was absent in all cases. Outside the setting of an intussusception and if viral cytopathic changes are not seen on routine histology, adenovirus IHC is not recommended in cases of acute appendicitis.