Lemmel syndrome: an uncommon complication of periampular duodenal diverticulum.

Lemmel's syndrome consists of obstructive jaundice due to compression of a periampular duodenal diverticulum (DDP), in the absence of choledocholithiasis or tumor. DDP are pseudodiverticula without a muscle layer within a radius of 2-3 centimeters from the ampulla of Vater. They rarely cause obstructive jaundice, although the prevalence is estimated at up to 22 % according to the sensitivity of the diagnostic test. They are usually incidental findings, but up to 1-5 % can be complicated with diverticulitis, bleeding, perforation, obstructive jaundice (Lemmel syndrome), choledocholithiasis, pancreatitis or cholangitis.