Rare Case of Duplication Cyst was Misdiagnosed as Pancreatic Pseudocyst

Abstract

A 7-year-old boy presents with a history of recurrent pancreatitis. His abdominal pain started in 2007, but his first episode of pancreatitis was in January 2010. Since that time has had at least five known episodes of pancreatitis with mild elevation of his amylase and lipase (range: 200 -300). There is no history of abdominal trauma and he had negative genetic testing for the hereditary pancreatitis (CFTR, PRSS1, and SPINK1 gene mutations). He had numerous imaging studies revealing a persistent cystic lesion near the pancreatic head, since his first episode of pancreatitis. Computed tomography of the abdomen showed thick-walled U-shaped cystic structure lying between the head of the pancreas, the inferior gastric antrum and the proximal descending duodenum. An abdominal US demonstrated a bi-lobed thick-walled cystic mass with a positive rim sign. Recurrent pancreatitis is uncommon in pediatric patients. Causes of recurrent pancreatitis in pediatrics are different than those in adults. While hereditary pancreatitis is one of the causes, the genetic testing was negative and there was no sign of pancreatic injury or inflammation in any of the images. Pancreatic pseudocyst is a complication of acute pancreatitis and usually has a thin wall instead of a thick wall, and it's unlikely to be present during the first episode of pancreatitis. Foregut duplication cyst is a rare (about 1 in 4,500) congenital anomaly that can happen anywhere throughout the GI tract. The US finding of a rim sign is a typical appearance of a duplication cyst and usually is managed by surgical resection. Even though foregut duplication is a rare congenital anomaly, it should always be considered in the differential diagnosis of cases of chronic pancreatis, especially with the presence of thick walled cystic formation on imaging studies.