Appendicitis on the Wrong Side: A Case of Left-Sided Acute Appendicitis With Intestinal Nonrotation

Left-sided acute appendicitis (LSAA) is a rare clinical entity, most commonly associated with midgut malrotation (MM) or situs viscerum inversus (SVI). Its atypical presentation poses a significant diagnostic challenge for emergency physicians, radiologists, and surgeons. We report the case of a 53-year-old man who presented with a two-day history of left-sided abdominal pain, fever, and vomiting. Laboratory investigations revealed marked leukocytosis. Abdominal ultrasonography identified an appendix-like structure with surrounding inflammation in the left iliac fossa. Contrast-enhanced computed tomography (CT) of the abdomen confirmed midgut nonrotation, with the ascending colon positioned on the left side and an abnormal superior mesenteric artery-to-vein relationship. The patient underwent open appendectomy through a midline incision. Intraoperative findings confirmed LSAA with large bowel nonrotation. The postoperative course was complicated by peritonitis, which was managed with surgical intervention and broad-spectrum antibiotics. At the 21-day follow-up, the patient was asymptomatic. This case highlights the importance of maintaining a high index of suspicion for LSAA in patients presenting with atypical left lower quadrant pain. Thorough preoperative imaging, particularly CT, is essential for accurate diagnosis and operative planning. Prompt surgical management remains the cornerstone of treatment to prevent life-threatening complications.