Imaging-Guided Localization for Surgical Retrieval of a Rare Complicated Retained Appendicolith

Background: Retained appendicolith related abscess formation is rare and carries challenging management options. We describe a unique case of a patient who presented with right upper quadrant pain tenderness that is clinically mimicking acute cholecystitis which turned out to be a perihepatic abscess caused by a dropped migrated appendicolith two and half years following a laparoscopic appendectomy.Aims: To report a case of a perihepatic abscess complicating migrated appendicolith after laparoscopic appendectomy and stress the importance of imaging-guided localization for surgical planning.Case Report: On January 2012, a 34-year old male patient presented to Montreal General Hospital, Montreal, Quebec, Canada, with a right upper abdominal pain, fever and mildshortness of breath. On physical examination, he was hemodynamically stable, but febrile of 38.9º C. Abdominal examination revealed right upper quadrant tenderness otherwise unremarkable. Blood tests resulted in elevated white blood cells count (16x10³/μL). Abdominal ultrasound showed normally appearing gallbladder with an unexplained perihepatic collection containing internally air locules and an 8 mm radiopaque appendicolith. Review of his previous imaging revealed a retained appendicolith at right subdiaphragmatic space. The abscess was immediately drained and the patient came back 6 months later for surgical retrieval of this appendicolith after ultrasound guided localisation. Conclusion: Dropped appendicolith related complication has increased since the introduction of laparoscopic appendectomy. Therefore, it should be suspected in cases of unexplained intraperitoneal abscess formation. Imaging guided localization can ease surgical retrieval.