CASE 14086 Published on 18.03.2017

Secondary Omental Infarction

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Daniel Eiroa, Mª Luisa Nieto Morales, Adán Bello Báez, Víctor Vázquez Sánchez, Sonia Benítez Rivero, Yasmín El Khatib Ghzal.

Hospital Universitario Nuestra Señora de Candelaria,Hospital Universitario Nuestra Señora de Candelaria,Servicio de Radiología (Department of Radiology); Carretera del Rosario, 145 38010 Santa Cruz de Tenerife, Spain; Email:contrasteyodado@gmail.com
Patient

77 years, male

Categories
Area of Interest Abdomen ; Imaging Technique CT
Clinical History
A 77-year-old patient who had undergone a right hemicolectomy less than a month before presented in the emergency room with right lower quadrant and middle lower quadrant pain and tenderness. No fever was reported. Lab tests showed mild leukocytosis and anaemia.
Imaging Findings
Given the patient's history, a computed tomography (CT) was performed, in which an extensive area of fat stranding was found spreadin from the pelvis at the level of the supravesical fossa to the mesotransverse colon (epigastric region), with some free fluid involving the root of the mesentery and between small vowel loops. A halo of hyperattenuating tissue, which was more evident on the pelvic component of the mass and was interpreted as thickening of the mesenteric layers, was also found. As the condition was treated medically, no histological proof was obtained.
Discussion
Omental infarction is one of the diseased included under the term intraperitoneal focal fat infarction [1] and is a rare cause of acute abdomen resulting from compromise of the vascular structures of the greater omentum.

The greater omentum is a double layer of peritoneum that extends inferiorly from the greater curvature of the stomach, turns superiorly on itself to drape over the transverse colon, and extends to the retroperitoneal pancreas. Its blood its supplied by both right and left gastroepiploic arteries.

This disease has a non-specific clinical presentation, with signs and symptoms that comprise acute abdominal pain, right lower quadrant pain and tenderness, and abscence of fever. It may be either primary; more frequent in the right lower quadrant, as a result of a mechanical or haemodynamic compromise; or secondary, particularly to surgery, abdominal trauma or inflammation of the omentum. The secondary form normally presents at the site of initial insult.

The greater omentum appears on CT as a band of fatty tissue that contains small vessels and is located just anterior to the transverse colon. It has a variable thickness, which depends primarily on the weight of the individual. Segmental omental infarction typically occurs on the right (mimicking appendicitis or gallbladder disease), a predilection that has been attributed to an embryologic variant of the blood supply of the right portion of the omentum, which predisposes it to venous thrombosis
Reactive bowel wall thickening may occur, but the inflammatory process in the omentum usually is disproportionately more severe.

Useful procedures for the diagnosis of omental infarction include ultrasound (US) and computed tomography (CT). The characteristic finding on the former is a focal area of hyperechogenicity in the omental fat. On the latter, the findings comprise a focal area of fat stranding, which may vary in size; a peripheral halo of increased attenuation; and, in cases where there is a mechanical cause, a swirling of the omental vessels (whirlpool sign).

The main differentials are epiploic appendagitis, which is more usual on the left side and is usually smaller than 5 cm, and mesenteric panniculitis, which is commonly originated in the mesenteric root.

Omental infarction is often self-limiting and can be managed conservatively. If complications such as an abscess occur, surgery or radiological drainage is needed.
Differential Diagnosis List
Omental Infarction
Omental Infarction
Epiploic Appendagitis
Mesenteric Panniculitis
Final Diagnosis
Omental Infarction
Case information
URL: https://eurorad.org/case/14086
DOI: 10.1594/EURORAD/CASE.14086
ISSN: 1563-4086
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