Incidental Finding of an Infarcted Epiploic Appendage Attached to the Sigmoid Colon

DISCUSSION

As noted previously, epiploic appendages can be distributed throughout the colon but are more often concentrated in the sigmoid colon.³ They are absent from the rectum.^3,5 Epiploic appendages usually measure 1 to 2 cm in length and 2 to 5 cm in thickness.³ They receive blood supply from 1 or 2 small end arteries branching from the vasa recta longa of the colon and are drained by a single vein.^9,10 Epiploic appendagitis occurs when an epiploic appendage becomes torsed, causing obstruction of the vascular or venous supply that leads to ischemia.^5,11 Epiploic appendagitis can also occur from embolic or thrombotic causes.¹ Epiploic appendagitis is a rare condition, with a frequency of 1.3% and an incidence of 8.8 cases per million annually.¹² However, the incidence may be increasing because of advancements in diagnostic imaging.

Epiploic appendagitis is associated with obesity, hernia, and strenuous exercise^5,8,11 and commonly occurs in people in the fourth and fifth decades of life, predominantly in males.⁸ Epiploic appendagitis typically presents with sudden onset of localized left or right lower quadrant acute abdominal pain. Most patients describe the pain as a dull, nonmigratory, localized, constant ache.¹³ Epiploic appendagitis is rarely associated with other symptoms such as nausea, vomiting, diarrhea, constipation, and fever.¹¹ Therefore, epiploic appendagitis should be considered as a potential diagnosis in patients with acute localized nonmigratory abdominal pain in the absence of the aforementioned symptoms.

Patients with epiploic appendagitis typically have normal vital signs.¹¹ Laboratory workup is generally unremarkable with a slight increase in serum levels of C-reactive protein and leukocyte count.^10,14 Diagnosis can be made via CT scan, ultrasound, and MRI.^5-8 The classic CT findings of epiploic appendagitis are (1) an ovoid lesion with fat attenuation surrounded by a thin hyperdense rim (hyperattenuating ring sign), (2) mild bowel wall thickening, and (3) central high-attenuation focus within the fatty lesion (central dot sign), indicative of a thrombosed vein in the inflamed epiploic appendage.¹ On ultrasound, an epiploic appendagitis lesion appears as a noncompressible, solid, hyperechoic mass attached to the colon.¹⁵ No blood flow to the lesion is observed on color Doppler signaling.¹⁵ MRI in patients with epiploic appendagitis shows an oval-shaped fat mass with a central dot on both T1- and T2-weighted images, with an enhancing rim seen on post-gadolinium T1-weighted fat-saturated images.¹⁶

The clinical features of epiploic appendagitis often resemble those of diverticulitis or acute appendicitis.^5,13 Other conditions that may mimic epiploic appendagitis include acute omental infarction, mesenteric panniculitis, sclerosing mesenteritis, and primary tumors or metastases involving the mesocolon.⁵ On CT, acute diverticulitis, in contrast to epiploic appendagitis, shows colonic diverticula with associated inflammation or abscess formation in the mesocolon and colonic wall thickening.⁵ Furthermore, patients with acute diverticulitis are more likely to present with symptoms such as fever, nausea, vomiting, elevated white blood cell count, and rebound tenderness that are uncommon in patients with epiploic appendagitis.⁵ On CT, an omental infarction usually shows as a larger lesion compared to epiploic appendagitis and lacks the hyperattenuating ring sign seen in epiploic appendagitis. Additionally, omental infarction primarily affects pediatric patients, whereas epiploic appendagitis is more commonly seen in adults.⁵ Sclerosing mesenteritis typically occurs in individuals in the sixth to seventh decades of life and has a higher incidence in males. Sclerosing mesenteritis can present with symptoms such as abdominal pain, fever, nausea, vomiting, diarrhea, and weight loss.⁵ Nevertheless, taking a thorough history and performing a physical examination, including a gynecologic examination for females, are essential to determine the cause of abdominal pain. For females, therefore, the differential diagnosis should include conditions such as ovarian torsion, ovarian cyst rupture, and ectopic pregnancy. Our patient's pain was possibly caused by epiploic appendagitis but may have been exacerbated by her abnormal uterine bleeding disorder.

Epiploic appendagitis is usually self-limiting and can be treated conservatively with NSAIDs.^5,7 Patients with epiploic appendagitis have also been treated with a combination of NSAIDs and antibiotics,⁷ although the treatment will depend on the patient's symptoms. Symptoms typically resolve within several days to weeks of conservative management. If symptoms do not improve, surgery is warranted.^7,8 Surgical excision of inflamed epiploic appendages is the most effective treatment for patients with recurrent epiploic appendagitis and for patients with complications such as intussusception, adhesions, and abscess formation.⁸