Paraumbilical Pain, Nausea, Vomiting

On examination, tense abdomen was palpable.

Figure 1. On plain CT abdomen axial, sagittal, and coronal images, a blind-ending fluid filled structure is noted on the anti-mesenteric border of the terminal ileum which appears to be intussuscepting into the terminal ileum.

Figure 2. On CECT abdomen axial, sagittal, and coronal images, a blind-ending fluid filled structure is noted on the anti-mesenteric border of the terminal ileum which appears to be intussuscepting into the terminal ileum with contrast enhancement.

There is twisting of mesentery and collapsed bowel loops is noted at terminal ileum in pelvic region.

Meckel’s diverticulum appears to be intussuscepting into the terminal ileum, resulting in the “pseudolipoma” sign as a result of invagination of the mesentery and fat of Meckel’s diverticulum into terminal ileum.

Meckel diverticulum is the most common congenital anomaly of the gastrointestinal tract, occurring in 2%–3% of the population.

The omphalomesenteric (vitelline) duct is the embryonic communication between the yolk sac and the developing midgut.

The omphalomesenteric duct will continue to grow if it fails to completely atrophy and disintegrate.

Ileoileal intussusception into the patent duct may occur, appearing clinically as ileal prolapse at the umbilicus.

Heterotopic tissue is found in approximately 50% of resected Meckel diverticula.

Reported complication rates range from 4% to 40%, with complications including bleeding, bowel obstruction, enterolith formation, retention of foreign bodies, inflammation (diverticulitis or ulceration), and neoplasm.

Hemorrhage accounts for up to 30% of symptomatic Meckel cases.

Bowel obstruction accounts for up to 40% of symptomatic Meckel’s diverticula.

Enteroliths can be seen in 3%–10% of Meckel’s diverticula.

Diverticulitis commonly occurs secondary to acid secretion from ectopic gastric mucosa.

The most frequently reported neoplasm complicating a Meckel’s diverticulum is carcinoid tumor.

Conventional radiographic examination is of limited value and is usually unrevealing.

Meckel’s diverticulum is not often seen on routine barium studies because of its small ostium, filling with intestinal contents, and peristalsis with rapid emptying.

Although of limited value, sonography has been used for the investigation of Meckel’s diverticulum.

On CT, Meckel’s diverticulum is difficult to distinguish from normal small bowel in uncomplicated cases.

Angiography can show the persistent omphalomesenteric artery in most individuals with a Meckel’s diverticulum who present with chronic gastrointestinal bleeding.

Scintigraphy with 99mTc-Na-pertechnetate has only minor diagnostic value and a limited sensitivity of 60% in diagnosing Meckel’s diverticulum.

Meckel diverticulum may invaginate or invert into the small intestinal lumen.

The principal differential diagnosis for an inverted Meckel diverticulum on CT scans is a lipoma.

CT characteristically shows the inverted diverticulum as a central core of fat attenuation surrounded by a collar of soft-tissue attenuation.