Idiopathic segmental infarction of the greater omentum (ISIGO): a case report and literature review

Introduction and importance: Idiopathic segmental infarction of the greater omentum (ISIGO) is a rare cause of acute abdominal pain and often mimics appendicitis and cholecystitis. Contrast-enhanced computed tomography (CT) is the most reliable imaging modality and can support conservative management in stable patients. However, conservative treatment may fail and require surgery. Presentation of case: A 55-year-old overweight man presented with 1 week of right-sided abdominal pain with recent worsening despite outpatient medical therapy. He was hemodynamically stable but had right upper quadrant tenderness and localized guarding. Laboratory testing showed an elevated C-reactive protein level with a normal leukocyte count and normal liver biochemistry results. CT demonstrated inflammatory fat stranding of the right greater omentum with a hyperdense rim, consistent with right-sided omental infarction. Given the persistent symptoms and CT findings, diagnostic laparoscopy was performed, which confirmed ischemic omentum with hemorrhagic peritoneal fluid. Laparoscopic segmental omentectomy was completed without complications. Histopathology confirmed omental infarction. The patient was discharged on postoperative day 1 and remained asymptomatic at the 6-week follow-up. Clinical discussion: ISIGO remains under-recognized, with evidence limited to isolated case reports and small series. CT typically shows fat stranding with a hyperdense rim, although overlap exists with other causes of focal fat inflammation. Recent literature supports conservative management in stable patients, reserving surgery for cases of diagnostic uncertainty or failure of symptomatic treatment. Conclusion: ISIGO should be included in the differential diagnosis of acute abdominal pain. CT enables diagnosis, and laparoscopy is a reasonable option when symptoms persist despite pain management, or when diagnostic uncertainty remains.