Internal herniation through a defect in the transverse mesocolon.

Internal hernias are rare, constituting 5.8% of all intestinal obstruction cases. Congenital transverse mesocolon hernias in adults are specifically rare. We hereby present a case of an adult female presenting with acute intestinal obstruction. Her CT scan showed classic signs of internal herniations: 'Whirlpool sign', crowding of bowel loops in the upper compartment and the absence of caecum from the Right Iliac Fossa. At operation, she was found to have a congenital defect in the transverse mesocolon, through which have herniated the terminal ileum, caecum and the proximal half of the ascending colon. They have furthermore rotated 360° about the axis of the pedicle forming a volvulus. The bowel was viable. The herniated bowel was derotated, and reduced through the defect, the defect was closed with polydioxanone sutures, and the caecum and ascending colon was fixed to the lateral abdominal wall.