Omental infarction is a rare cause of acute abdomen. It typically simulates acute appendicitis, with clinical features that include abdominal pain of a few days’ duration, most often localized in the right lower or upper quadrant.
The most frequent cause of non–torsion-related omental infarction is venous insufficiency due to trauma or thrombosis of the omental veins. Factors that predispose people to omental infarction include obesity, strenuous activity, congestive heart failure, digitalis administration, recent abdominal surgery, and abdominal trauma.
Omental infarction occurs in a fair number of pediatric patients (approximately 15% of cases). Infarction of the omentum is less common than infarction of either the small or the large bowel because abundant collateral vessels perfuse the omentum.
Signs & symptoms
The manifestation of right-sided pain may lead to clinical misdiagnosis of omental infarction as appendicitis or cholecystitis; thus, imaging is required to achieve an accurate diagnosis and to avoid unnecessary laparotomy and antibiotic therapy.
Radiological Findings on CT
- Solitary large nonenhancing omental mass with heterogeneous attenuation
- Most often located in the right lower quadrant, deep to the rectus abdominis muscle and either anterior to the transverse colon or anteromedial to the ascending colon.
- Although omental infarction may have a CT appearance that resembles that of acute epiploic appendagitis, it lacks the hyperattenuating ring that is seen in epiploic appendagitis. In addition, whereas the central focal lesion in acute epiploic appendagitis is most often less than 5 cm long and is located adjacent to the sigmoid colon, the lesion in omental infarction is larger and most commonly is located next to the cecum or the ascending colon.