Identification of the cause of abdominal pain on CT abdomen in a patient with multiple incidental findings

URL:https://www.eurorad.org/case/14131

CLINICAL HISTORY

A 19-year-old female presented in the emergency department with complaints of acute abdominal pain in the left iliac fossa, associated with nausea. There was no history of fever or diarrhea. The cell count was normal. The patient underwent USG abdomen followed by Contrast-enhanced CT (CECT) of the abdomen and pelvis.

IMAGING FINDINGS

USG abdomen shows a small well defined echogenic lesion with a thin hypoechoic rim in the left iliac fossa. The lesion appears hypovascular on color Doppler. Minimal perilesional fluid can be seen (Fig. 1).

CECT of the abdomen and pelvis shows approx 2.8cm size fat-density ovoid structure just anterior to the descending colon with a thin high-density peripheral rim (suggestive of inflamed peritoneum of the epiploic appendage) and perilesional minimal inflammatory fat stranding. No bowel wall thickening was seen (Fig. 2).

A radiological diagnosis of primary epiploic appendagitis was made.

Incidentally findings:

1. Normal head and uncinate process of the pancreas with abrupt cut-off. Non-visualization of neck, body, and tail of the pancreas. Suggestive of Dorsal Agenesis of Pancreas (Fig. 1, 3).

2. Bilateral renal fossa was empty with a solitary kidney with lobulations seen in the right iliac fossa with malrotation axis. Excretory scan shows a single PC system with a single ureter. S/o Solitary Ectopic right kidney (Fig. 4).

3. Banana-shaped small uterus deviated to the right of midline. No rudimentary horn on the left side. Possibility of Unicornuate uterus.

DISCUSSION

Epiploic appendagitis is an uncommon, inflammatory process of the epiploic appendix, mostly self-limiting. They are peritoneal outpouchings arising from the serosal surface of the colon and contain adipose tissue and vessels [1].

The most common part of the colon affected in decreasing order of frequency is the sigmoid, descending, cecum, and ascending colon.

It may be primary or secondary to adjacent pathology (e.g.diverticulitis) [1]. Patients most commonly present with localized acute abdominal pain. WBC count is usually normal.

The pathogenesis is thought to be due to torsion of a large and pedunculated appendage epiploicae, or spontaneous thrombosis of the venous outflow, resulting in ischemia and necrosis [2].

Primary epiploic appendagitis is difficult to diagnose clinically because of the lack of pathognomonic clinical features and because symptoms may mimic those of acute appendicitis or diverticulitis depending upon its site.

On sonography, it appears as a solid, hyperechoic, noncompressible ovoid mass surrounded by a subtle hypoechoic line [2].

The CT appearance of acute epiploic appendagitis shows the presence of approx. 1.5- to 3.5-cm diameter fat-density lesion with surrounding inflammatory changes abutting the anterior wall of the colon. Although the presence of a central high-attenuation focus within the fat is a helpful finding in making the diagnosis, its absence does not exclude the diagnosis of acute epiploic appendagitis. The central high-density focus is believed to represent a thrombosed vessel within the inflammed appendix epiploica [2].

Epiploic appendagitis is a self-limiting disease, conservative treatment with analgesics and NSAIDs is usually sufficient and thus correct identification on CT prevents unnecessary surgery [2].

Dorsal pancreatic agenesis presents clinically with abdominal pain which can be due to pancreatitis although it is an incidental finding on imaging in most patients. On imaging this gives an appearance of foreshortened pancreatic parenchyma with abrupt termination beyond the head [3].

A unicornuate uterus results from normal development of one Müllerian duct and near complete to complete arrested development of the contralateral duct. Approximately 40% of unicornuate uteri have renal anomalies ipsilateral to the absent or rudimentary horn, with renal agenesis being the most common as in our case [4].

The embryological development of these organs - the pancreas, kidney and uterus - is different since the pancreas is endodermal and the genitourinary system mesodermal in origin. Occurrence of anomalies involving all these organs in a single patient suggest possible existence of yet unknown common developmental/genetic signaling pathway shared between these organ systems.

DIFFERENTIAL DIAGNOSIS LIST

Acute epiploic appendagitis with dorsal pancreatic agenesis,unilateral renal agenesis,unicornuate uterus

Mesenteric panniculitis

Omental infarct

FINAL DIAGNOSIS

Acute epiploic appendagitis with dorsal pancreatic agenesis,unilateral renal agenesis,unicornuate uterus