Incidental Asymptomatic Right Sided Paraduodenal Hernia: A Rare Congenital Anomaly

Abstract

Purpose: Paraduodenal hernia is a very rare congenital anomaly, accounting for half of all internal hernias. Small bowel gets entrapped in a peritoneum-lined sac behind the mesocolon. We present one of the first incidentally diagnosed asymptomatic case of right paraduodenal hernia. A 50-year old female with chronic hepatitis C genotype 3 with an elevated alpha feto protein level of 16.32 IU/ml on routine work up underwent a CT abdomen to look for liver lesions. Incidentally seen was a right paraduodenal hernia. Patient was asymptomatic with normal physical exam. Surgical correction was offered but patient refused. Right paraduodenal hernia results from failure of complete midgut rotation during embryogenesis with resultant small bowel entrapment on the right side behind the mesocolon. Left paraduodenal hernia is more common and herniates through a defect in the descending mesocolon into the fossa of Landzert. Repeated herniation increases defect size, leads to adhesions, obstruction or strangulation. Clinical findings vary from mild intermittent abdominal complaints to acute obstruction, volvulus and infarction. On CT left paraduodenal hernia is seen as a saclike cluster of small bowel loops in the left upper quadrant between pancreatic body-tail and stomach, displacing the inferior mesenteric vein anterolaterally. With right paraduodenal hernia, small bowel loops lie on the right behind the superior mesenteric vessels, below the transverse portion of the duodenum displacing the right colic vein anteriorly. Other findings include mass effect on posterior stomach wall, engorgement and crowding of mesenteric vessels at mouth of hernial sac, depression of transverse colon and small bowel obstruction. Upper GI series may show entire small bowel to one side of the abdomen. Diagnosis is by clinical and radiographic findings. Management is by surgical repair. In conclusion paraduodenal hernia, especially right sided hernia is extremely rare causing internal herniation of the jejunal loops that can progress to bowel obstruction or strangulation without surgery.Figure: Jejunal loops inferolateral to the 2nd part of duodenum with abnormal course of jejunal arteries.