Histopathological surprises: When eosinophils invade the appendix

The vermiform appendix is a vestigial organ in the human body. Inflammation of this organ is quite common leading to acute appendicitis. Globally, acute appendicitis remains one of the leading causes of surgical emergencies. Uncomplicated appendicitis (UA) on histopathological examination shows neutrophilic infiltration in the lamina propria. Here, we report a case of acute eosinophilic appendicitis (AEA) that mimicked UA but had predominantly eosinophils in lamina propria. A 63-year-old woman came with complaints of pain in the right lower abdominal quadrant and nausea for 2 days. Computed tomography showed a swollen appendix. She was diagnosed with UA and underwent appendectomy, but the final histopathological diagnosis was of an AEA. This case suggests that AEA may be misdiagnosed as UA, which is often managed with antibiotics. AEA should be suspected when there is an inadequate response to antibiotic therapy.