CASE 8946 Published on 15.11.2010

Epiploic appendagitis: MRI findings

Section

Abdominal imaging

Case Type

Clinical Cases

Authors

Tonolini M, Ravelli A, Bianco R.
Department of Radiology, "Luigi Sacco" Hospital, Milan, Italy.

Patient

32 years, female

Categories
Area of Interest Abdomen ; Imaging Technique MR, CT
Clinical History
This young woman was admitted to the Emergency Department complaining of gradually increasing abdominal pain in the left lower quadrant over the last 5 days, without fever. Physical examination revealed a painful left lower quadrant on superficial and deep palpation. Her laboratory tests were normal.
Imaging Findings
In view of the patient’s young age, abdominal and pelvic MR was requested to search for a pathologic condition causing her symptoms. The only abnormal finding was the presence of a roundish soft tissue lesion measuring about 2,5 cm, closely adherent to the external (serosal) surface of the distal descending colon. The lesion showed an oedematous peripheral rim that enhanced after intravenous gadolinium contrast, and a central portion with signal paralleling that of fat in all sequences. Mild inflammatory stranding in the surrounding fat planes was associated.
The diagnosis was confirmed by means of a focused unenhanced CT acquisition of the lower abdomen, which yielded that this pericolonic lesion showed the peculiar appearance of epiploic appendagitis (EA), with peripheral soft tissue, adipose center, and mild stranding of the surrounding fat planes.
The patient recovered fully following conservative treatment during 2 weeks.
Discussion
Epiploic appendagitis (EA) is an uncommon, self-limiting inflammatory process involving the colonic epiploic appendices, which represent normal anatomic structures consisting in peritoneum-covered fatty bands measuring about 2,5 cm.
EA usually manifests with acute onset of pain, most often in the left lower quadrant. White blood cell count and body temperature are often normal. Torsion of epiploic appendages, with resultant vascular occlusion that leads to ischemia, has been implicated as main cause of acute EA and usually occurs in the descending and sigmoid colon. Awareness of imaging features in acute EA is important because this condition can be managed medically.

CT is considered as imaging modality of choice because of its cost-effectiveness and widespread availability. The epiploic appendages become visible only when they are inflamed and/or surrounded by fluid. Acute EA appears on CT as an oval lesion measuring less than 5 cm in diameter (typical diameter range, 1.5–3.5 cm), with attenuation equivalent to that of fat, abutting the colonic wall, and surrounded by inflammatory changes. The wall of the adjacent colon may be thickened but is most often normal. Thickening of the parietal peritoneum, secondary to the spread of inflammation, is also observed.
Ultrasonography occasionally allows the diagnosis of EA by demonstrating an oval non-compressible hyperechoic mass, adjacent to the colon, without central blood flow on colour Doppler images.

Reported experiences with MR in the diagnosis of EA are still scarce. MR represents, as our case exemplifies, because of lacking ionizing radiation and an excellent safety profile of gadolinium-based contrast agents, a promising alternative to CT. MR is very useful particularly in patients for whom the risk of radiation is a major concern, such as children, adolescents, and pregnant women, or in case of contraindication to iodinated contrast agent due to previous allergic reactions. T1- and T2-weighted MR images show a pericolonic roundish focal lesion with signal intensity paralleling that of fat. Contrast-enhanced T1-weighted images depict an enhancing rim surrounding the fatty lesion.
The inherent high soft tissue contrast of MR allows to confidently recognize the central adipose tissue portion of EA and the inflammatory changes in the surrounding fat planes, even without contrast medium administration. Thus, unenhanced MR acquisition is a useful diagnostic tool in patients with impaired renal function.

The therapeutic approach in EA is conservative with oral anti-inflammatory medication, antibiotics are not routinely indicated.
Differential Diagnosis List
Epiploic appendagitis
Acute diverticulitis
Omental infarction
Final Diagnosis
Epiploic appendagitis
Case information
URL: https://www.eurorad.org/case/8946
DOI: 10.1594/EURORAD/CASE.8946
ISSN: 1563-4086