Groove Pancreatitis Associated with a Large Pseudocyst in the Muscular Layer of the Duodenal Wall: A Case Report

Abstract

We report a case of groove pancreatitis (GP) with a pseudocyst in the muscular layer on the right side of the duodenum-the first such case reported to our knowledge. A 55-year-old man reporting abdominal discomfort for 6 months and vomiting for 1 month was found in abdominal enhanced computed tomography (CT) and magnetic resonance imaging (MRI) to have a 10×5 cm cystic lesion along the right side wall of the duodenal second to third portions and a 1 cm low-enhanced nodule of the pancreatic head. Upper gastrointestinal tract (GI) series and GI Endoscopy showed duodenal stenosis. Serum DUPAN-2 was elevated at 747 U/ml. Under a tentative diagnosis of pancreatic head cancer and duodenal stenosis, we conducted pancreaticoduodenectomy. The resected specimen showed a white 1 cm nodule of the pancreatic head, and a 7×5 cm cystic lesion of the duodenum. Histologically, the pancreatic nodule was focal fibrosis with chronic pancreatitis and the cystic lesion was in the muscular layer of the duodenal wall. The final diagnosis was GP with focal fibrosis and an intramural pancreatic duodenal wall pseudocyst. GP is difficult to diagnose preoperatively because imaging of a GP-associated nodule resembles that of pancreatic head cancer.