In the Groove: A Case Series of Groove Pancreatitis

Abstract

Background: Groove pancreatitis is an uncommon and under-recognized form of focal chronic pancreatitis of the “sliding plane” between the pancreatic head and duodenum due to obstruction of pancreatic juice flow through the minor duct. This process creates clinical, radiographic, and gross pathologic features that can mimic pancreatic adenocarcinoma. Presentation: We present a series of three male patients ultimately diagnosed with groove pancreatitis. Case 1: A 45 year-old smoker with a history of chronic alcohol ingestion and multiple prior admissions for acute pancreatitis with pancreatic pseudocysts and changes of chronic pancreatitis on imaging. On his seventh admission for pancreatitis, CT scan demonstrated a “double duct sign,” signs of gastric outlet obstruction (GOO), and duodenal thickening which an endoscope was unable to traverse. He subsequently went for pancreaticoduodenectomy and pathology demonstrated chronic pancreatitis, Brunner gland hyperplasia, and no evidence of malignancy. Case 2: A 56 year-old former smoker with severe vascular disease presented with generalized weakness and melena. A CT scan revealed a prominent pancreatic head and a hypodense duodenal mass. Symptomatic GOO lead to pancreaticoduodenectomy and pathology revealed extensive scaring of the pancreatic head and duodenal musculature with numerous cysts, some of which had ruptured suggesting duct malformation. Case 3: A 66 year-old former smoker presented with one year of intermittent bloating, post-prandial abdominal pain, early satiety, nausea, vomiting, and a 20 pound weight loss. Imaging revealed GOO from a duodenal mass and a cystic lesion in the pancreatic head. Endoscopy revealed a large circumferential polypoid mass in the duodenal bulb. Biopsy of this revealed prominent Brunner glands without malignancy. He was treated with gastrojejunostomy leaving the inflammatory mass behind. To date his symptoms have improved and all repeat biopsies were negative for malignancy. Discussion: This case series exemplifies the risk factors and classical findings of groove pancreatitis such as smoking history, duodenal stenosis, “pseudotumor” appearance of the periduodenal space, and Brunner gland hypertrophy. The variations in presentation as demonstrated above can lead to an intricate and diagnostically challenging work-up to rule out malignancy. We also highlight a patient successfully treated without surgical removal of the affected pancreas and duodenum.