Original Articles

Primary Epiploic Appendagitis: Clinical and Radiological Manifestations

Nurith Hiller MD, Daniel Berelowitz MD and Irith Hadas-Halpern MD Department of Radiology, Shaare Zedek Medical Center, Jerusalem, Israel

Key words: epiploic , appendagitis, imaging

Abstract operation for this self-limited condition. Ultrasonography Background: Primary epiploic appendagitis is a rela- and especially computed tomography are the best diagnostic tively rare condition in which torsion and inflammation of techniques and are of paramount importance in differ- an epiploic appendix result in localized abdominal pain. entiating PEA from clinically similar but surgically treated This is a non-surgical situation that clinically mimics other conditions. conditions requiring surgery such as acute diverticulitis or On the basis of five new cases of PEA and in the light of . the worldwide literature, we present a summary of the main Objective: To investigate the clinical, laboratory and clinical, CT and ultrasonographic features of this condition. radiological findings of the disease. Methods: During the years 199588 five patients with Patients and Methods primary epiploic appendigitis were diagnosed at our As a general rule in our institution, patients with suspected institution. The clinical, laboratory and imaging results diverticulitis undergo emergency CT whereas suspected were summarized and compared to previously reported appendicitis is imaged with abdominal ultrasound. In the series. Emphasis was placed on the computed tomography presence of severe abdominal pain of unclear origin both CT findings, which are the gold standard for diagnosis. and ultrasound are usually performed. Results: All our patients (two males and three females, Between January 1995 and May 1998 PEA was diagnosed mean age 47 years) presented with left lower quadrant in five patients on the basis of CT findings. Plain abdominal abdominal pain. CT proved to be the imaging modality of X-ray examinations were done in all five and ultrasound choice in all patients by showing a pericolic fatty mass with examination prior to CT in three. The CT images were an increased attenuation as compared to normal abdominal performed in a spiral scanner (Helicat II, Elscint, Israel) fat. In all cases the mass was surrounded by a high using oral and IV contrast medium. Ultrasound was attenuation rim, and focal stranding of the fat was performed with a high resolution 5 MHz convex-array observed. In no case was there thickening of the adjacent transducer, focusing on the point of maximum tenderness. bowel wall. This serves as an important, and previously All patients were referred from the emergency depart- unreported, clue for diagnosis. ment. The patients  two men and three women aged 2358 Conclusion: Primary epiploic appendagitis is a rela- years (mean 46.8)  had progressive pain in the left lower tively rare condition that may be clinically misdiagnosed, quadrant. One patient presented with acute pain while the resulting in unnecessary surgical intervention. Judicious other four had a more prolonged course of the pain for 15 interpretation of CT may lead to early diagnosis and ensure days (mean 3.75) prior to admission. One patient also had proper conservative treatment. nausea, vomiting and diarrhea. Two of the patients had normal body temperature and three exhibited low fever IMAJ 2000;2:896898 (37.5(C). Physical examination revealed exacerbation of the pain with the Valsalva maneuver in all five patients, as well Epiploic appendices are fatty tags attached to the large as guarding and significant rebound tenderness in the left intestine wall along its entire course. Primary epiploic lower quadrant. The white blood cell count was slightly appendagitis is a general term denoting torsion, ischemia or elevated in all patients, ranging from 7,500 to 12,000/mm3. inflammation of an epiploic appendix [1]. PEA is relatively rare and usually presents clinically with localized abdominal Results pain that may give rise to an erroneous diagnosis of acute Plain abdominal film revealed dilated small bowel loops in diverticulitis or appendicitis. It is imperative to reach a the left abdomen in two patients, a large amount of bowel diagnosis preoperatively in order to avoid an unnecessary content in two, and was normal in one patient. In the three ______patients who underwent ultrasound examination, a non- PEA = primary epiploic appendagitis compressible, hyperechoic round (n=1) or oval (n=2) mass

896 N. Hiller et al. IMAJ · Vol 2 · December 2000 Original Articles é

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Figure 1. CT of the lower abdomen demonstrating an oval-shaped Figure 2. A further example of PEA anterior to the lesion with fatty attenuation adjacent to the (arrow- (arrow). Despite marked inflammation adjacent to the colon,there heads). The mass is bordered by a thick hyperattenuating rim. Note is no bowel wall thickening. mild stranding of the surrounding fat and thickening of the parietal . Several linear densities are visible within the fatty mass,consistent with thrombosed vessels (arrow). Marked mass approximately 57% located in the sigmoid colon, followed by effect on the adjacent colon is demonstrated without bowel wall the (26%), (9%), thickening. (6%) and descending colon (2%) [1]. Epiploic appendagitis can be primary or secondary. was found at the point of maximum tenderness surrounded Secondary epiploic appendagitis occurs in a neighboring by a hypoechoic rim. The mass was adjacent to the colon in organ due to an inflammatory process such as diverticulitis, all cases and the preliminary ultrasonographic diagnosis was appendicitis, cholecystitis, etc. PEA, on the other hand, is a of an inflamed colonic diverticule. fairly rare situation attributable to either spontaneous In all cases CT depicted a pericolic anterior (n=2) or torsion or venous thrombosis of an epiploic appendix, antero-lateral (n=3) oval mass with fatty attenuation, followed by ischemic or hemorrhagic infarction and inflam- adjacent to the serosal surface of the colon [Figure 1]. The mation [14]. fatty mass had increased attenuation as compared to other Each epiploic appendix receives its blood supply from one areas of normal omental and mesenteric fat [Figure 2]. The or two small end-arteries branching from the vasa recta of size of the masses ranged between 15x7.5 and 40x20 mm the colon. This limited blood supply in combination with (average 26.8x14 mm). All masses had a high attenuation their long pedunculated shape and free motility makes rim that was 410 mm (mean 8.2 mm) thick and circum- appendices epiploicae prone to torsion and consequent scribed the fatty mass. Marked peri-appendageal fat strand- ischemic infarction [1,5]. In some cases severe inflammation ing and thickening of the visceral peritoneum was noted. can ensue with no vascular impairment [6]. Since the The effect of the mass on the adjacent bowel was seen in appendices of the sigmoid and cecum are the most four patients, and a central dot or small linear density inside prominent and elongated these organs are the main sites the mass was noted in three patients [Figure 1]. The parietal of involvement. peritoneum was thickened in three patients. In no case was Thomas et al. [1] reported the largest series of PEA and adjacent bowel wall thickening demonstrated. found an equal incidence in male and females. All patients Surgery was performed in one patient because of presented with localized abdominal pain and tenderness of aggravation of the symptoms. The other four patients several days duration; fever and leukocytosis were common responded well to conservative treatment with antibiotics, and 25% had gastrointestinal symptoms. In contrast, the showing gradual amelioration of symptoms and resolution of series of Molla et al. [7] found the cardinal symptom to be leukocytosis. There was no recurrence of symptoms. The acute localized abdominal pain and no patient had fever or duration of hospitalization was 48 days (mean 5.8). gastrointestinal discomfort. The clinical findings in our patients resemble those reported by Thomass group [1], Discussion except for one instance where the presenting symptom was Appendices epiploicae are small sacs of visceral peritoneum sudden acute localized abdominal pain. It seems that an filled with fat and blood vessels. They project from the two accurate diagnosis of PEA based on clinical manifestations non-mesenteric taeniae coli from the cecum down to the alone is elusive. recto-sigmoid. Usually 0.55 cm long and 12 cm thick, a Plain abdominal radiography is unhelpful in the diagnosis length up to 15 cm has been reported [2,3]. Each individual of PEA. The positive role of ultrasonography in PEA is well has on average about 100 appendices epiploicae [4], with documented in the literature [7,8]. The main sonographic

IMAJ · Vol 2 · December 2000 Epiploic Appendigitis 897 Original Articles features are a hyperechoic, non-compressible ovoid mass ness of the condition, judicious interpretation of imaging located anterior to the colon at the point of maximum modalities and knowledge of the spectrum of radiological tenderness. Usually a hypoechoic rim is encountered. The findings are essential for establishing the diagnosis and mass is hyperechoic due to its fat content as well as the avoiding unnecessary surgical intervention. presence of hemorrhagic necrosis [8]. An erroneous ______diagnosis of diverticulitis is often entertained based on the ultrasound findings. CT is even more reliable than ultra- References sound in defining PEA and is the preferred imaging modality. 1. Thomas SH, Rosato EE, Patterson LT. Epiploic appendagitis. Surg Gynecol The characteristic CT features of PEA are an anterior or Obstet 1974;38:235. antero-lateral oval or round pericolic mass 14cmin 2. Lynn TE, Dockerty MD, Waugh JM. A clinico-pathologic study of the diameter with fatty attenuation. The mass exhibits a epiploic appendages. Surg Gynecol Obstet 1956;103:42333. 3. Fieber SS, Forman J. Appendices epiploicae:clinical and pathological thickened hyperdense rim that represents a swelling of considerations:report of 3 cases and statistical analysis of 105 cases. Arch the serosa with fibrino-leukocytic exudate. In some instan- Surg 1953;66:32938. ces a dot or fine line of high attenuation is noted in the fatty 4. Pines B, Rabinovitch J, Biller SB. Primary torsion and infarction of the mass, presumably caused by thrombosed vessels in the appendices epiploicae. Arch Surg 1941;42:77587. epiploic appendix [8]. 5. Ross JA. Vascular loop in the appendices epiploicae:their anatomy and surgical significance, with a review of the surgical pathology of appendices None of our patients showed thickening of the adjacent epiplocae. Br J Surg 1950;37:4646. colonic wall, and this can serve as an important clue for 6. Ghahremani GG, White EM, Heff FL, Gore RM, Miller JW, Christ ML. differentiating PEA from other localized pericolic inflamma- Appendices epiploicae of the colon:radiologic and pathologic features. tory conditions such as diverticulitis. Radiographics 1992;12:5977. 7. Molla E, Ripolles T, Martinez MJ, Morote V, Rosello-Sastve E. Primary The treatment for PEA is conservative, with antibiotics, epiploic appendagitis:US and CT findings. Eur Radiol 1998;8:4358. while other conditions such as acute appendicitis or 8. Rioux M, Langis P. Primary epiploic appendagitis:clinical, US and CT cholecystitis generally require surgical intervention. It is findings in 14 cases. Radiology 1994;191:5236. therefore essential to identify PEA to prevent unnecessary ______surgery. Correspondence: Dr. N. Hiller, 36 Bernstein Street, Jerusalem 96920, In conclusion, the clinical signs and symptoms of PEA are Israel. Phone: (972-2) 642-0065, 053-802805, Fax: (972-2) 643-0337, non-specific and often lead to clinical misdiagnosis. Aware- email: [email protected]

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Giving Form to CTLA-4 Interactions Signals delivered by cell surface receptor CTLA-4 are ment of such complexes. Their data suggest that CTLA-4 critical for ensuring that the T cells do not overstep their formsdimersthatareunlikethosemadebyother mark when responding to antigen. How this is accom- members of the immunoglobulin supergene family in that plished is not fully understood, but it involves at least in they can interact simultaneously with two of its natural B7 part direct inhibitory signals. The efficiency of these ligands. This organization could help to explain the signals likely relies on the assembly of inhibitory signaling proficiency of CTLA-4 in regulating the immune re- complexes at the interface between the antigen-present- sponses. ing cell and the T cell. Ostrov et al. have solved the crystal structure of CTLA-4 and in so doing revealed how the organization of this receptor might facilitate the arrange- Science 2000;290:816

898 N. Hiller et al. IMAJ · Vol 2 · December 2000