Diagnosis of groove pancreatitis in patient with chronic pancreatitis and recurrent abdominal pain

Clinical History

A 62-year-old man was urgently admitted to our hospital with severe epigastric pain and vomiting. The patient had a history of chronic pancreatitis for the past 2 years. Laboratory findings showed: Amylase 421 U/l; Lipase 82 U/l;Ca 19.9 and CEA in normal range.

Imaging Findings

The patient, due to recurrent abdominal pain, had undergone MRI in 2011 (Figure 1) that showed a thickening of the duodenal wall with a cyst in its context.
MRCP revealed the regularity of the biliary tree. Ducts were not dilated, neither in intrahepatic branches nor in the main one (Figure 2).
In 2012 for a flare of symptoms, a CT with contrast administration was conducted (Figure 3). Images showed the presence of a pancreatic pseudocyst; moreover, in pancreatic arterial phase (35 second after contrast administration) a hypodense region in duodenal wall was observed. The contrast enhancement of cyst peripheral ring was detected.
Collateral signs such as the regularity of pancreatic tail which was rescued from the pathologic process and the normality of liver and biliary tree helped to formulate the correct diagnosis (Figure 4).
Clinic, laboratory analysis and imaging contributed to the final diagnosis of groove pancreatitis. The patient underwent pancreaticoduodenectomy.

Discussion

First reported by Becker in 1973 [1], groove pancreatitis (GP) was defined as the presence of focal pancreatic disease localized in an area comprising the C-loop of the duodenum and the head of the pancreas (Figure 5) [2].
Two forms of GS were described: the “segmental” form, which involves the pancreatic head; and the “pure” form, which affects the groove only, sparing the pancreatic head [3].
In recent years, Adsay and Zamboni recognized two types of pancreatitis characterized by cystic or solid lesions respectively [4].
The GP pathogenesis is uncertain: disturbances of pancreatic outflow through the Santorini duct (minor papilla) are frequently associated factors. Chronic alcohol intake and/or smoking increase the viscosity of the pancreatic juice causing pancreatic duct calcification and subsequent outflow obstruction of the pancreatic juices. Hyperplasia of the Brunner’s glands may also lead to stasis of pancreatic juices in the dorsal pancreas resulting in pancreatitis at the anatomical groove [5].
The clinical manifestations comprise upper abdominal pain, weight loss, postprandial vomiting and nausea due to duodenal stenosis, but jaundice is rare. Clinical complications associated with GP are related to inflammatory changes affecting the duodenal wall [6].
Computed tomography (CT), Magnetic Resonance Imaging (MRI), and endoscopic sonography (EUS) are modalities commonly used in the assessment of pancreatic masses. In GP, CT shows a poorly enhancing hypodense area between the duodenum and the pancreatic head. Others CT features include thickening of the duodenal wall and occasionally paraduodenal cysts. In the segmental form, there can be a hypodense non-enhancing focal lesion within the upper part of the pancreatic head that is difficult to differentiate from pancreatic carcinoma.
On MRI, GP appears as a sheet-like hypointense mass on T1-weighted images that is isointense or slightly hyperintense relative to the pancreatic parenchyma on T2-weighted images. On EUS, it has a varied appearance, including a hypoechoic or heterogeneous mass along the descending duodenum with periduodenal and intramural fluid collections [7].
Serum pancreatic (amylase, lipase, and elastase) and hepatic enzyme levels are sometimes slightly elevated. Serum levels of carcinoembryonic antigen and carbohydrate antigen (CA 19-9) are usually normal [8].
Initial non-surgical treatments are more frequently employed. These conservative options involve cessation of smoking and alcohol, adequate analgesia, resting the pancreas and in some instances endoscopic stenting of the minor papilla. However, these measures are only temporary and surgery is inevitable when symptoms fail to improve or, in many cases, when there is uncertainty about the diagnosis [5].

Differential Diagnosis List

Final Diagnosis

Groove pancreatitis

URL:	https://www.eurorad.org/case/10588
DOI:	10.1594/EURORAD/CASE.10588
ISSN:	1563-4086