Presentation
Abdominal pain.
Patient Data
Abnormal rounded cluster of proximal small bowel, left of midline, converging towards a neck slightly posterior and lateral to the inferior mesenteric vein. There is mild mass effect on the left pararenal space/kidney. No obstruction.
Case Discussion
Operative note excerpt: 'Intraoperatively, there was an approximately 30 cm section of small bowel which had herniated posterior to the inferior mesenteric vein. This was easily reducible and all the bowel appeared viable. The defect was closed."
To ensure that radiologists remain confused about internal hernias, the congenital paraduodenal fossa that is responsible for the left paraduodenal hernia has been named the "paraduodenal fossa of Landzert." This is an uncommon congenital peritoneal fossa behind the descending mesocolon, resulting from a failure of fusion with the posterior parietal peritoneum. Left paraduodenal hernias are more common than right.
An important landmark is the IMV which is along the anteromedial edge of the fossa of Landzert, which can be seen in this case. In other words, confirm this diagnosis by checking if the IMV is anterior and medial to where you think the hernia orifice is.