Groove Pancreatitis: A Rare form of Chronic Pancreatitis

Groove pancreatitis is a rare form of chronic pancreatitis affecting the "groove" of the pancreas among the pancreatic head, duodenum, and common bile duct. The exact cause is unknown, although there are associations with long-term alcohol abuse, smoking, peptic ulcer disease, heterotopic pancreas, gastric resection, biliary disease, and anatomical or functional obstruction of the minor papilla. The diagnosis can be challenging. Endoscopic ultrasound (EUS) and magnetic resonance cholangiopancreatography are the preferred imaging modalities. The treatment of choice is conservative although surgical intervention can sometimes be required.

A 57-year-old male with a history of human immunodeficiency virus and hepatitis B presented with 4 days of epigastric pain. Abdominal exam revealed absent bowel sounds and epigastric tenderness. He had a creatinine of 1.72 mg/dL, potassium of 2.9 mmol/L, and a normal lipase level of 86 U/L. Liver enzymes and total bilirubin were normal. Computed tomography abdomen showed high-grade obstruction of the second portion of the duodenum without any obvious mass. An esophagogastroduodenoscopy showed a mass at the duodenal bulb causing luminal narrowing, with biopsies negative for malignancy. Magnetic resonance imaging revealed a mass in the region of the pancreatic head and descending duodenum. EUS revealed a 3 cm mass in the region of pancreatic head with irregular borders and no vascular invasion. Fine needle aspiration (FNA) was nondiagnostic. The patient then underwent a Whipple's procedure. Pathology of these specimens was negative for malignancy but was consistent with para-duodenal or groove pancreatitis.

The low incidence of groove pancreatitis is partly due to lack of familiarity with the disease. Groove pancreatitis should be considered in the differential for patients presenting with pancreatic head lesions and no cholestatic jaundice, especially when a duodenal obstruction is present, and neither duodenal biopsies nor pancreatic head FNA confirm adenocarcinoma.