We report the unusual case of a 71-year-old female who had recurrent presentations over three years with right loin abscess appearing to originate from a retroperitoneal collection. She was initially diagnosed with a right psoas abscess of unknown aetiology and was managed with open surgical drainage of this collection. However, further investigations after recurrent admissions raised the suspicion of appendicitis as the underlying pathology. Despite two unremarkable colonoscopies, she proceeded to undergo diagnostic laparoscopy and appendicectomy, with histopathology ultimately showing chronic appendicitis. She made an unremarkable recovery.