Appendiceal Hydatid Disease Presenting as Acute Appendicitis: A Case Report and Review of the Literature

Appendiceal hydatid disease is an exceptionally rare manifestation of cystic echinococcosis and may be indistinguishable from routine acute appendicitis before surgery.We report a 43-year-old man who presented with a two-day history of right lower-quadrant abdominal pain, anorexia, and nausea.Clinical examination demonstrated localized tenderness at McBurney's point with signs of localized peritoneal irritation.Laboratory investigations showed leukocytosis and an elevated C-reactive protein level.Abdominal ultrasonography demonstrated a non-compressible, inflamed appendix measuring approximately 9 mm in diameter with a fecalith-like intraluminal structure, and emergency open appendectomy was undertaken for presumed acute appendicitis.Intraoperatively, an unexpected cystic lesion was identified adjacent to the appendiceal base and ruptured during dissection, with extrusion of whitish membrane-like material.The operative field was immediately irrigated with hypertonic saline, and no intraoperative anaphylactic reaction occurred.Histopathological examination demonstrated laminated and germinal layers consistent with cystic echinococcosis.The patient subsequently received albendazole 400 mg twice daily in three 28-day cycles separated by 14-day treatment-free intervals.Follow-up computed tomography performed three months after surgery demonstrated no residual or additional hydatid cysts at that time, and the patient remained clinically well without evidence of recurrence during 12 months of follow-up.This case, considered alongside the published literature, highlights the diagnostic difficulty of appendiceal hydatid disease, the importance of cautious handling of unexpected cystic appendiceal lesions, and the need for postoperative antiparasitic treatment and imaging surveillance.