Sunday, November 10, 2013

EPIPLOIC APPENDAGITIS - An ultrasound diagnosis

Epiploic  appendages are peritoneal pouches that arise from the serosal surface of the colon. These are composed of adipose tissue and attached to colon by vascular  stalk  , multiple in count [ approx 100 ] ,& have a length range of  about 0.5–5 cm. Those located near the sigmoid colon are the largest in size . Epiploic appendages are usually not found near the rectum. The appendages are arranged in two rows: one row medial to the tenia libera, and the other lateral to the tenia omentalis of the colon .


Epiploic appendagitis is an uncommon self limiting inflammatory or  ischaemic condition affecting the colonic  epiploic appendage. Appendagitis  may be primary[ spontaneous ] or secondary to adjacent pathology , with more affection or predilection for sigmoid colon , presumably due to larger appendices. The condition most commonly manifests in the 4th to 5th decades of life, predominantly in men & obese individuals . Torsion of epiploic appendage pedicle , with resultant vascular occlusion or venous occlusion that leads to ischemia[ ischemic necrosis], has been implicated as the cause of acute epiploic appendagitis.  Acute epiploic appendagitis is also seen to be associated with  hernia, and unaccustomed exercise. Mostly  it is a self limiting  disease  , and  very uncommonly it may result in adhesion, bowel obstruction, intussusception, intraperitoneal loose body, peritonitis, and/or focal abscess formation.


Clinically patients present with acute abdominal pain and guarding in local area at the site of involvement [ that is usually lower quadrant , more common in left iliac fossa] . On the basis of clinical manifestations alone, acute epiploic appendagitis is mis-diagnosed in most of the cases , and or  often its being mistaken for acute diverticulitis.  Unlike acute epiploic appendagitis, acute diverticulitis is more likely to cause evenly distributed lower abdominal pain and  associated with nausea, fever, and leukocytosis.  On the contrary most patients with acute epiploic appendagitis do not manifest  any change in their bowel habits, and only a few cases report constipation or diarrhea.

Differential diagnosis ;
1] acute omental infarction
2] diverticulitis
3]sclerosing mesenteritis or mesenteric panniculitis
4] primary tumor or metastasis that involves peritoneum and mesocolon.
Ultrasound Findings
The site of maximum tenderness[mostly left iliac fossa] is the region of interest for ultrasound evaluation . There is evidence of a round to oval echogenic  noncompressible  mass noted , with no internal vascularity on doppler, and surrounded by a subtle hypoechoic line . The lesion is  typically 2 - 5 cm in maximal diameter adjacent and anterior to colon , and just deep to abdominal wall . The mass exert slight compressive effect on colonic loop  , and usually not  associated with colonic mural thickening  , or local or free peritoneal fluid .
In my series of 7 patients  [ 6 M & 2F, age range 35 to 48 yrs] , six cases presented with pain left iliac fossa , & one case with pain in right iliac fossa.  All cases were showed classical ultrasound findings of epiploic appendagitis with no bowel thickening or ascites . In all cases no leucocytosis was observed in lab. tests. In one case with pain right iliac fossa , the d/d was with acute appendicitis , but appendix and ileo-cecal region was seen separately & normally on ultrasound  .

Fig 1- Shows a normal  descending colonic epiploic appendage : An oval elongated echogenic structure [ arrow] attached to DC loop, nicely depicted due to presence of ascites[FL]


Fig 2 - Epiploic appendagitis, case A : LIF scan shows a well defined oval echogenic mass [bet cursors] surrounded by hypoechoic halo , just deep to abd wall 

Fig 3 - LIF scan of same case A , mass with no internal vascularity on power  doppler

Fig 4 - CT scan sagittal reconstruction image of  case A, shows a well defined oval hypodense fat density lesion along descending colonic loop[arrow within circle]

Fig 5 - Epiploic appendagitis, Case B, LIF scan shows a well defined  oval echogenic mass[ twin arrow] between sigmoid loop[single arrow] and abd wall

Fig 6 - Epiploic appendagitis, case C, LIF scan shows an oval echogenic mass with hypoechoic rim[arrows] adjacent to normally appearing sigmoid cooln



CT findings-
A fat-density ovoid lesion  adjacent to colon, size varying 1.5 - 3.5cm in diameter , with thin high-density rim , surrounding inflammatory fat stranding, and thickening of the adjacent peritoneum. A central hyperdense dot like area also appreciated representing the thrombosed vascular pedicle. As a chronic sequele an infarcted appendix epiploica  may calcify, and may detach to form an intraperitoneal loose body.

Treatment and prognosis

Epiploic appendagitis is a self limiting disease, and thus a correct diagnosis is important with imaging modalities to prevents unnecessary surgery. 
 Ref.