Groove Pancreatitis: A common Condition That Is Uncommonly Diagnosed Preoperatively

1Dalhousie Medical School; 2Division of Gastroenterology, Department of Medicine; 3Department of Radiology, Dalhousie University, Halifax, Nova Scotia Correspondence: Dr Geoffrey S Williams, Division of Gastroenterology, Department of Medicine, Dalhousie University, Room 920, Victoria General Hospital, 1276 Southpark Street, Halifax, Nova Scotia B3H 2Y9. Telephone 902-473-4585, fax 902-473-5548, e-mail gswillia@dal.ca Received for publication February 2, 2014. Accepted February 11, 2014 CASE PRESENTATION A 47-year-old woman presented with a two-week history of severe right upper-quadrant abdominal pain radiating to the back. She reported no jaundice, weight loss of 4.5 kg over six months, no history of alcohol consumption, and no family history of pancreatic disease or autoimmune disease. Her symptoms briefly subsided then resumed two months later, prompting investigation. Abdominal ultrasound revealed a dilated common bile duct (CBD) with a maximum diameter of 10 mm and a possible hypoechoic lesion arising from the pancreatic head, raising the possibility of a neoplasm (Figure 1). Computed tomography (CT) scan revealed two calcifications in the pancreatic head within the distal pancreatic duct, consistent with a pancreatic mass, along with stricture of the distal CBD and enlarged regional lymph nodes (Figure 2). Bloodwork revealed elevated alkaline phosphatase (196 U/L) and alanine aminotransferase (139 U/L) levels, normal total bilirubin levels and a mildly elevated CA 19-9 tumour marker level (42.5 kU/L). Subsequent referral for endoscopic retrograde cholangiopancreatography (ERCP) revealed a smooth, 2 cm stricture of the distal CBD; brush cytology was negative for malignant cells. A 9 cm, 10 Fr plastic biliary stent was placed across the stricture and the patient experienced resolution of her abdominal pain. It was believed that this was a benign distal CBD stricture; therefore, further workup was performed for causes of pancreatitis. The immunoglobulin G4 level was normal, as was the antinuclear antibody level. Metabolic workup, including triglycerides and calcium, was normal. Magnetic resonance imaging (MRI) of abdomen and pelvis revealed multiple, variable size cystic lesions, the largest measuring up to 1.6 cm and seen in close relation to the medial duodenal wall, along with bulkiness of appearance of the pancreatic head and uncinate process, and no definite pancreatic or ductal masses identified (Figure 3). Repeat ERCP performed seven weeks after the initial ERCP showed persistent smooth stricture of the distant CBD consistent with chronic pancreatitis (Figure 4). Again, cytology was negative for malignant cells. Following a hepatobiliary surgical consultation, an endoscopic ultrasound (EUS) with fine-needle aspiration was performed, revealing a hypoechoic, heterogeneous pancreatic head with two small cysts between the duodenal wall and pancreatic head, with associated parenchymal calcifications in the pancreatic head. The pancreatic body and tail appeared normal with normal pancreatic duct. Fine-needle aspiration was negative for malignant cells. The MRI was then reviewed again with an expert in gastrointestinal radiographic imaging. The radiologist believed that the imaging characteristics were highly suggestive of groove pancreatitis (GP). The patient underwent two additional ERCPs in an attempt to dilate the distal CBD stricture. The attempts at dilation were unsuccessful and she was subsequently referred for surgical management of the stricture. The patient was scheduled for exploratory laparotomy pancreaticoduodenectomy, but intraoperative exploration revealed an extremely hard, chronically inflamed gland that was better treated by Images of the month