Clinical History
A 59-year-old man presented to the emergency department with fever and abdominal pain, two weeks after a laparoscopic left hemicolectomy due to a colon adenocarcinoma. Laboratory results revealed leukocytosis and high levels of CRP. A diagnosis of infected omental infarction and anastomotic leak was made and elective surgery was performed.
Imaging Findings
CT study revealed a heterogeneous collection in the left subphrenic space with a hazy area of fat and bubbles. These findings are compatible with post-surgical infected omental infarction. CT also showed another abscess in the left hemiabdomen, where the patient previously had a drainage tube. In addition, inflammatory changes, intraabdominal haematoma and extraluminal bubbles near colonic anatomoses were found, being suggestive of an anastomotic leak.
Discussion
The greater omentum is a two-layered fold of peritoneum that hangs down from the stomach. It extends from the greater curvature of the stomach superiorly and the ventral surface of the transverse colon inferiorly. It is mobile and contains fat and blood vessels [2, 3].
Omental infarction results from a vascular compromise due to venous stasis and thrombosis, with subsequent oedema and congestion. It can be primary or secondary to a traumatic injury, surgical trauma or inflammation.
Primary omental infarction is generally seen at the right lower quadrant, while secondary omental infarction appears near the surgical site [3]. At the physical examination, patients generally develop acute abdominal pain and focal tenderness. Gastrointestinal symptoms and fever are generally absent, and blood tests unaltered [2].
CT is the best imaging technique for diagnosing omental infarction, although ultrasounds are recommended for paediatric patients. The characteristic finding in the US is a focal area of increased echogenicity of the omental fat. On CT images, omental infarction appears as a large and encapsulated non-enhancing mass with heterogeneous fatty attenuation. When the omental infarction is infected, there is a rim-enhanced collection with variable amounts of fat-fluid level and gas. It is generally surrounded by inflammatory changes and free abdominal fluid [1-3].
The difference between a peritoneal abscess and omental infarction is the presence of fat. Both entities have a rim-enhancement and may contain bubbles; but only omental infarction presents fat - fluid level [1].
Omental infarction is a self-limiting entity that normally calls for conservative management. Surgical intervention is reserved for cases where there is not a prompt response or when there are complications such as infection or abscess formation [3].
Differential Diagnosis List
Infected omental infarction
Epiploic appendagitis
Liposarcoma
Peritoneal abscess
Final Diagnosis
Infected omental infarction
