“Tethered Fat Sign”: The Sonographic Sign of Omental Infarction

Abstract

Our purpose is to describe the ultrasound sign for a correct non-invasive diagnosis of omental infarction in children. From January 2014 to December 2018, a total of 234 children (109 boys and 125 girls, age range 3À15 y) with acute right-sided abdominal pain, admitted to our hospital with a presumptive diagnosis of acute appendicitis, were prospectively evaluated. In all patients, abdominal ultrasound was performed, and the omental fat was always evaluated. In 228 patients, the omental fat resulted to be normal or hyperechogenic, never tethered, and they results affected by other causes of abdominal pain different from omental infarction (such as appendicitis, pancreatitis, urolithiasis and others). In the remaining 6 children, we found a hyperechoic mass between the anterior abdominal wall and the ascending or transverse colon in the right abdomen quadrant, suggesting the diagnosis of omental infarction. This subhepatic mass was always tethered to the abdominal wall, motionless during respiratory excursions. We named this finding the "tethered fat sign." The diagnosis was confirmed with laparoscopy in 4 children. The other 2 children were treated with conservative therapy. In these 2 patients, a sonographic follow-up was performed, showing a progressive reduction in size of the right-sided hyperechoic mass. In conclusion, our study suggests that the presence of the "tethered fat sign" may be an accurate sonographic sign for non-invasive diagnosis of omental infarction in children.

Omental infarction diagnosed by computed tomography, missed with ultrasonography: A case report

“…The male to female ratio is usually 2:1[ 9 ]. OI was reported in 15% of children and 85% of adults, so it is very rare in children and very difficult to diagnose at first examination[ 10 ]. Abdominal pain is common in children and most are non-surgical diseases such as constipation and enteritis.…”

Spontaneous omental infarction: A rare case of acute abdomen

“…Ultrasound may show an oval- or triangular-shaped hyperechoic lesion corresponding to the greater omentum, but CT would usually reveal a mass of mixed attenuation due to the fatty and non-fatty elements of the mass. 11 , 12 CT abdomen is used in several studies for the accurate localization of the pathology. 13 , 14 Concentric linear strands or the “whirl” sign with hyper attenuated streaky infiltration are the radiological signs specific to omental infarction and torsion.In our patient these features were not evident.…”

Omental Infarction in a Child—Conservative Management as an Effective and Safe Strategy in Diagnosis and Treatment

“…Omental infarction (OI) occurs in approximately 0.1% to 0.5% of children undergoing surgery for suspected appendicitis [1,8,9], which makes OI a rare cause of acute abdominal pain in children [10]. For the first time, an idiopathic omental infarct was described by Bush in 1896 [1].…”

“…Ischemia of the omentum and associated infarction cause a local inflammatory response. Either laboratory tests are normal or abnormalities such as leukocytosis with neutrophilia and increased CRP levels are observed [10,13].…”

“…In our case, the abdominal ultrasound showed mesenteric adipose tissue with increased echogenicity and the presence of free fluid. Fifteen percent of all reported cases of omental infarction are children [10]. Those under 4 years of age are particularly rarely affected, which may be the effect of a relatively low amount of intra-abdominal fat and omentum at this age [4,8].…”