Enterobius vermicularis Infestation: A Rare Cause of Appendicitis.

Enterobius vermicularis (E. vermicularis, pinworm) is a common gastrointestinal parasite in children, occasionally implicated in appendiceal pathology. We report a case of a seven-year-old autistic male who presented with a three-day history of right iliac fossa pain, fever, nausea, and vomiting. Clinical and laboratory findings suggested acute appendicitis, prompting diagnostic laparoscopy and appendicectomy. Intraoperatively, a mildly inflamed appendix was noted with multiple mesenteric lymph nodes and visible roundworms at the appendiceal base, which were carefully suctioned out. Histopathology confirmed E. vermicularis infestation without definitive acute inflammatory changes. The patient had an uneventful recovery with postoperative anthelmintic therapy for the household. While the role of E. vermicularis in true appendicitis remains debated, its presence within the appendix can cause symptoms mimicking acute appendicitis. Given the diagnostic uncertainty and potential risk of appendiceal obstruction or secondary infection, appendicectomy remains a definitive and justified treatment in such cases, ensuring symptom resolution and preventing complications.