Pericaecal hernia (alternative plural: herniae) is a rare type of internal hernia.

Epidemiology

It accounts for only 6-13% of internal abdominal hernias.

Clinical presentation

Clinical symptoms are often characterised by episodes of intense lower abdominal pain, like a colicky right lower quadrant pain very similar to the appendiceal pain, often causing confusion.

Pathology

Four subtypes (ileocolic, retrocaecal, ileocaecal, and paracaecal) of herniations occur in the pericaecal fossa (located behind the caecum and ascending colon and is limited by the parietocaecal fold outward and the mesentericocaecal fold inward). It is due to acquired or congenital defects in the caecal mesentery.

Retrocaecal hernia is the most common subtype caused by herniation of ileal loops through a defect in the caecal mesentery and the right paracolic gutter.

There is no real importance to the subtype of pericaecal hernia, as treatment is the same for all subtypes ^1,3.

Radiographic features

Fluoroscopy 

Delayed radiograph series of the small bowel or a barium enema examination may show retrograde opacification of the terminal ileum.

CT

These hernias can often be confidently diagnosed as a cluster of bowel loops (usually ileal) located posteriorly and laterally to the normal caecum, occasionally extending into the right paracolic gutter. In addition, a beaking appearance at the entrance of the hernia, and a dilated afferent small bowel loop and collapsed efferent loop in the transition zone may be seen. There might be evidence of small-bowel obstruction and mass effect displacing the caecum anteriorly and medially.