PRIMARY EPIPLOIC APPENDAGITIS: Clinical, US and CT Findings in 15 cases

Tai Van Le, Tai Anh Vo, Hai Thanh Phan, MD
MEDIC Medical Center, HCM City, Vietnam

ANATOMICAL REVIEW

Epiploic appendages are small peritoneal pouches that arise from the colon composed of fat tissue and blood vessels, 0.5 – 5 cm long. There are about 100 epiploic appendages (1).
Normal epiploic appendages are easily seen in cases of ascites at US and CT (2,3).


INTRODUCTION

Primary epiploic appendagitis (PEA) is a rare entity that usually mimicks others such as diverticulitis, appendicitis, right-sided segmental omental infarction (2,5,6,10).
Causes of PEA: torsion, spontaneous venous thrombosis (2,3,4,7,8,9,10).
vComplicated diverticulitis and acute appendicitis require surgical operation.
US can be used to help diagnose this entity in correlation with clinical and CT findings.

OBJECTIVE

To describe appearance at US of primary epiploic appendagitis (PEA) in correlation with CT findings, and evolution of PEA with conservative treatment.
To differentiate PEA requiring no surgery from other surgical entities.

MATERIALS & METHODS

All patients with sudden onset of acute abdominal pain were chosen for US exam.
From 2000 – 2003: 15 patients, 8 male and 7 female, age 8 – 67 (mean 41), suspected of having primary epiploic apppendagitis (PEA).
Ten cases were examined by US alone (n= 10), 5 cases by US & CT (n = 5).
R/ abd. pain: 2 cases (1 RUQ, 1 RLQ). L/ abd. pain: 13 cases, 1 of which had a palpable mass.
US criteria for diagnosis: a small, ovoid, solid, hyperechoic and non-compressible mass (4).
Based on CT findings: inflamed fat tissue adjacent to colon (2,3,4,7,8,9,10).
US machine with curve or linear probe (3.5 – 7.5 MHz), Toshiba SSH 250A & Aloka SSD Prosound 4000.

RESULTS

Position by US: A case was anterolateral to the ascending colon near cecum (Fig.6), 1 case adjacent to hepatic colonic flexure (Fig.5). Thirteen cases (n= 13): anterior or antero-lateral to the descending colon, 1 case located near splenic colonic flexure, 12 cases near sigmoid colon (Fig. 2,3,4).
US findings: In all cases, US detected an ovoid, solid, hyperechoic, and non-compres sible mass, sized 3 – 5 cm (Fig. 2,3,4,5,6).
CT findings: determined there was hyper-attenuating, inflamed fat tissue adjacent to colon (FIG. 2,3,4,6).
Laboratory Findings: Slightly elevated ESR. No or mild leucocytosis.
Clinical symptoms decreased after 7 – 12 days of medical treatment (analgesic, antibiotic) and disappeared completely after 2 weeks.

DISCUSSIONS

Clinical features: sudden & local abdominal pain with rebound tenderness; fever & diges- tive disorder (+/-); WBC & ESR mildly or not elevated.
US: a small, ovoid, and solid mass that was hyperechogenic, noncompressible & painful on palpation next to the descending/ ascending colon. This is similar to the literature.
CT: hyper-attenuation of fat tissue adjacent to colon.
In a study of Rioux et al (1994), epiploic appendagitis is self-limited and self-regressed, requiring only analgesics without surgery (4).
Clinical symptoms decrease after 7 – 12 days, and completely disappear after 2 weeks.
Different diagnosis: Omental infarction, diverticulitis, acute appendicitis.
Omental Infarction: rare, affects mostly adults, vascular occlusion common cause; most often RLQA at the level of umbilicus; also self-limited and autoreg- ressed.
•US: large-sized (> 5 cm).
•CT: heterogeneous attenuation (5,6).

In 2 cases of Right abdominal pain, clinicians suspected of acute appendicitis whereas US: PEA, regressed under conservative treatment and disappeared completely (Fig. 5,6).

CONCLUSIONS

PEA has characteristic US features.
PEA is not difficult to diagnose by US in combination with CT and clinical findings. CT determines there is inflamed fat tissue adjacent to colon.
PEA is self-limited, auto-regressed, and requires no surgery. This helps to prevent unnecessary surgical operation.

REFERENCES

1.Lorenzo E. Derchi. Appendices Epiploicae of the Large Bowel: sonographic Appearance and differentiation from peritoneal seeding, J Ultrasound Med 7:11-14, 1988
2.Ajay K. Singh, MD. Acute Epiploic Appendagitis and Its Mimics, RadioGraphics 2005;25:1521-1534
3.Patrick M. Rao. Primary Epiploic Appendagitis: Evolutionary Chang in CT Appearance, Radiology 1997;204:713-717
4.Rioux M, Lang P. Primary epiploic appendagitis: clinical, US, and CT findings in 14 cases. Radiology 1994; 191:523-526
5.Puylaert. Right-sided Segmental Infarction of the Omentum: Clinical, US, and CT Findings: Radiology 1992; 185:169-172
6.Matteo Baldisserotto, Omental Infarction in Children: Color Doppler Sonography Correlated with Surgery and Pathology Findings, AJR 2005; 184:156-162
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