A seven year old girl presents with right lower quadrant pain. Abdominal ultrasound revealed prominent reactive lymph nodes in the right lower quadrant and peri-umbilical region. Findings were suspicious for acute appendicitis.
Case Discussion
Adenovirus is a nonenveloped virus with a double stranded DNA genome that rarely infects the gastrointestinal tract. It has been described in association with mesenteric adenitis and ileocecal intussusception. In addition, it can induce a marked reactive lymphoid hyperplasia of the appendix that can mimic acute appendicitis clinically. In these cross-sections of the appendix, note the Cowdry type A eosinophilic nuclear inclusions in many of the enterocytes. Immunohistochemistry for adenovirus demonstrates strong nuclear staining within the mucosa.
This slide shows IHC stain. See related content for H&E stain.
Forse, C., Somers, G. Appendix, Adenovirus infection, IHC stain. Digital Laboratory Medicine Library, Dept of Laboratory Medicine & Pathobiology, University of Toronto. Published
. Accessed December 17, 2025. https://dev.dlml.cflabs.ca/image/appendix-adenovirus-infection-ihc-stain-lmp89787
