Fact-sheet: Epiploic appendagitis
  • Torsion of an epiploic appendage


Updated on 04/24/2026 at 10:19 AM

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Definition

Epiploic appendagitis is an acute inflammation or infarction of the epiploic appendages. These are small pedunculated fatty structures, expansions of the visceral peritoneal serosa, that surround the colon.

  • Mechanisms: Torsion of the vascular pedicle, spontaneous thrombosis of the draining vein, or more rarely, lymphoid inflammation.
  • Types: primary epiploic appendagitis = without an adjacent cause
  • secondary epiploic appendagitis = reactive to a nearby inflammatory focus such as diverticulitis.

Clinical features

The presentation often mimics a surgical emergency. Pain: Focal abdominal pain, sudden in onset, electively localized over the lesion (often left lower quadrant). Aggravating factors: Pain increased by coughing, deep breathing, or stretching. Physical findings: Localized tenderness, minimal guarding, but usually no marked febrile syndrome. Population: Common between 20 and 60 years of age (median 40 years), with overweight as a predisposing factor.

Laboratory findings

Laboratory findings most often normal.

A mild leukocytosis or a moderate elevation of CRP may be observed in some cases.

Radiography

Plain radiography is not a diagnostic examination for acute epiploic appendagitis.

It may, however, reveal sequelae = Peritoneal loose bodies: In cases of chronicity, the infarcted appendage may calcify and detach, forming a "peritoneal mouse" (mobile foreign body, calcified at the periphery).

Ultrasound

Characteristic findings at the point of maximal tenderness: Mass: Solid, hyperechoic, ovoid structure (2 to 4 cm), noncompressible and adherent to the colonic wall. Halo: Presence of a hypoechoic peripheral ring. Dynamics: The mass is fixed relative to the parietal peritoneum and does not move with respiratory motion. Doppler: Absence of internal flow (ischemia); flow may occasionally be seen at the periphery due to inflammatory reaction.

CT

Reference examination.

Contrast-enhanced acquisition showing:

  • Elementary lesion: Ovoid pericolic mass of fat density (1 to 4 cm), often on the antimesenteric side (between the wall and the colon).
  • Hyperdense ring sign: Thin peripheral ring (1 to 2 mm) corresponding to the inflamed visceral peritoneum.
  • "Dot sign": Linear or punctate hyperdense focus in the center of the fat, reflecting the thrombosed vein.
  • Adjacent reaction: Infiltration of the surrounding pericolic fat, thickening of the parietal peritoneum overlying the lesion.
  • Colonic status: The adjacent colonic wall is generally normal or only mildly thickened by contiguity, without marked luminal narrowing.
  • Key locations: Rectosigmoid (57%), ileocecal region (26%), ascending colon (9%).

Appendagite épiploïque TDM CT-scan appendagitis

MRI

Less commonly performed.

  • T1/T2 sequences: High signal (fat) with a central dot and a peripheral hypointense ring.
  • T1 C+ FatSat: Marked enhancement of the peripheral ring (sign of inflammation).

Management

The prognosis is excellent, with spontaneous resolution in about one week. Treatment: Conservative and symptomatic (analgesics, NSAIDs). Avoidance: No antibiotics or surgery (except in rare complications < 2.7%, such as obstruction or abscess). Follow-up: No follow-up imaging is indicated if the clinical course is favorable.

Differential diagnosis

Acute diverticulitis: Marked wall thickening, presence of diverticula, diffuse infiltration of the fat. Epiploic appendagitis accounts for 2 to 7% of suspected diverticulitis cases. Omental infarction (greater omentum): Larger "dirty" fat mass (3 to 5 cm), often located to the right of the transverse or ascending colon. Acute appendicitis: Distended blind-ending tubular structure (> 7 mm), frequent presence of an appendicolith. Mesenteric panniculitis: More diffuse involvement of the mesentery.