A Not-So-Groovy Masquerader: A Case Report of Groove Pancreatitis

Abstract

Background: Groove pancreatitis is an uncommon and under-recognized form of focal chronic pancreatitis of the area between the pancreatic head and duodenum due to obstruction of pancreatic juice flow in the minor duct. This disease entity creates a diagnostic challenge as clinical, radiographic, and gross pathologic features can mimic pancreatic adenocarcinoma. Case: A 54-year-old male former-smoker with a history of chronic alcohol consumption presented initially with refractory pyrosis and nausea. Esophagogastroduodenoscopy (EGD) demonstrated duodenal wall thickening and a CT scan of his abdomen revealed duodenitis and inflammation of the pancreatic head with fat stranding. He re-presented three years later with worsening epigastric pain and a 60 pound weight loss. Repeat CT scan revealed an infiltrating heterogeneously enhancing process between the descending duodenum and pancreatic head (Figure 1). Magnetic resonance cholangiopancreatography (MRCP) revealed a 2.7 x 2.3 x 2.3cm mass with soft tissue infiltration and narrowing of the distal common bile duct (CBD) concerning for possible malignancy. CA 19-9 and liver function tests were within normal limits. Continued abdominal pain, intolerance to oral intake, persistent nausea and vomiting, and continued weight loss lead to endoscopic ultrasound (EUS). This demonstrated diffuse pancreatic head and genu parenchymal abnormalities, a 10mm CBD, and enlarged peripancreatic lymph nodes. Repeat MRCP on subsequent admission again revealed focal groove-centric changes of acute and chronic pancreatitis with duodenal wall thickening. EGD/EUS with duodenal biopsies demonstrated focal duodenitis with prominent Brunner glands and fine needle aspiration of the mass revealed cellular atypia and chronic inflammation consistent with chronic pancreatitis and a diagnosis of groove pancreatitis was established.Figure 1Discussion: Groove pancreatitis poses a diagnostic challenge due to its malignancy-like presentation and clinical course. Many of the described risk factors and classical findings of groove pancreatitis were present in our patient including chronic tobacco and alcohol use, severe weight loss secondary to duodenal stenosis, sheet-like mass lesion in the periduodenal space, and prolonged time to diagnosis. However, his clinical course demonstrates the complex nature of this disease process, the close resemblance to pancreatic malignancy, and the difficulty in differentiating these two conditions to arrive at a diagnosis.